diff --git a/.github/workflows/python-release.yml b/.github/workflows/python-release.yml
index fc61205..00ebeb6 100644
--- a/.github/workflows/python-release.yml
+++ b/.github/workflows/python-release.yml
@@ -1,12 +1,17 @@
 name: Create and upload release
 
 on:
-  push:
-    tags:
-      - 'v*'
+  workflow_run:
+    workflows: ["Python Package using pip"]
+    types:
+      - completed
 
 jobs:
-  test-linux:
+  release:
+    # Only run if the triggering run was for a tag starting with v
+    if: >
+      github.event.workflow_run.conclusion == 'success' &&
+      startsWith(github.event.workflow_run.head_branch, 'v')
     runs-on: ubuntu-latest
     strategy:
       max-parallel: 5
@@ -14,34 +19,12 @@ jobs:
     steps:
     - uses: actions/checkout@v4
 
-    - name: Set up Python 3.11.2
-      uses: actions/setup-python@v3
+    - name: Download pytest-results artifact from previous workflow
+      uses: actions/download-artifact@v4
       with:
-        python-version: '3.11.2'
-    
-    - name: Add conda to system path
-      run: |
-        # $CONDA is an environment variable pointing to the root of the miniconda directory
-        echo $CONDA/bin >> $GITHUB_PATH
-    
-    - name: Install dependencies
-      run: |
-        conda env update --file environment.yaml
-    
-    - name: Lint with flake8
-      run: |
-        conda install flake8
-        # stop the build if there are Python syntax errors or undefined names
-        flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
-        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
-    
-    - name: Test with pytest
-      run: |
-        source activate bemol
-        pytest tests/ -vvs
-        # store the latest run results as release artifact
-        zip -r pytest-results.zip tests/results/
+        name: pytest-results
+        run-id: ${{ github.event.workflow_run.id }}
+        path: .
     
     - name: Create Release
       id: create_release
diff --git a/.github/workflows/python-test-conda.yml b/.github/workflows/python-test-pip.yml
similarity index 50%
rename from .github/workflows/python-test-conda.yml
rename to .github/workflows/python-test-pip.yml
index 3692735..0f851e7 100644
--- a/.github/workflows/python-test-conda.yml
+++ b/.github/workflows/python-test-pip.yml
@@ -1,6 +1,12 @@
-name: Python Package using Conda
+name: Python Package using pip
+
+on:
+  push:
+    branches:
+      - '*'
+    tags:
+      - '*'
 
-on: [push]
 
 jobs:
   test-linux:
@@ -16,15 +22,11 @@ jobs:
       with:
         python-version: '3.11.2'
     
-    - name: Add conda to system path
-      run: |
-        # $CONDA is an environment variable pointing to the root of the miniconda directory
-        echo $CONDA/bin >> $GITHUB_PATH
-    
     - name: Install dependencies
       run: |
-        conda env update --file environment.yaml
-        conda install flake8
+        python -m pip install --upgrade pip
+        pip install -r requirements.txt
+        pip install flake8
     
     - name: Lint with flake8
       run: |
@@ -33,15 +35,27 @@ jobs:
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
     
-    # TODO: conside the latest release, not a hardcoded one!
+    # considers the latest release, not a hardcoded one!
     - name: Get reference results
       run: |
-        curl -L -o pytest-results.zip "https://github.com/ifpen/bemol/releases/download/v0.0.1/pytest-results.zip"
+        URL=$(curl -s https://api.github.com/repos/ifpen/bemol/releases/latest \
+            | jq -r '.assets[] | select(.name=="pytest-results.zip") | .browser_download_url')
+        if [ -z "$URL" ] || [ "$URL" = "null" ]; then
+          echo "pytest-results.zip not found in latest release assets"
+          exit 1
+        fi
+        curl -L -o pytest-results.zip "$URL"
         unzip pytest-results.zip
         mv tests/results tests/ref/
 
     - name: Test with pytest
       run: |
-        source activate bemol
         pytest tests/ -vvs --reference tests/ref/
-    
\ No newline at end of file
+        zip -r pytest-results.zip tests/results
+
+    - name: Upload pytest-results artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: pytest-results
+        path: pytest-results.zip
+        retention-days: 0.020833 # 30 minutes
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index e9a6557..eef9504 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 **/__pycache__/
-**/.pytest_cache/
\ No newline at end of file
+**/.pytest_cache/
+
+/.bemol/
\ No newline at end of file
diff --git a/README.md b/README.md
index d7e7dd4..f869785 100644
--- a/README.md
+++ b/README.md
@@ -81,14 +81,25 @@ The library is based on [Numpy](https://numpy.org/), [Scipy](https://scipy.org/)
 [pytest](https://pytest.org/) is as well optional, used for the evaluation
 of the tests inside the `tests` sub-folder.
 
-The list of considered/tested versions are available in environment.yaml.
-For use with conda:
+The list of considered/tested versions are available in conda and pip formats.
 
-```bash
-conda env create -f environment.yaml
-```
+- For use with conda:
+
+  ```bash
+  conda env create -f environment.yaml
+  ```
+
+  Use `conda activate bemol` to use the env.
+
+- Using pip and venv:
+
+  ```bash
+  python3 -m venv .bemol
+  source .bemol/bin/activate
+  pip install -r requirements.txt
+  ```
 
-Use `conda activate bemol` to use the env.
+  Use `source .bemol/bin/activate` to use the env.
 
 ## Authors
 
diff --git a/bemol/bem.py b/bemol/bem.py
index 7e79f32..fe62ae3 100644
--- a/bemol/bem.py
+++ b/bemol/bem.py
@@ -5,60 +5,11 @@
 import numpy as np
 
 from . import rotor
-from . import secondary
+from . import correction
 from . import tools
 
 
 
-
-class Corrections(object):
-    """Class for storing corrections.
-
-    Consider all the corrections available in the secondary
-    models module. If not given by the user considers the base (empty)
-    correction with the default parameters.
-
-    Parameters
-    ----------
-    corrections : optional
-        dictionary or list with the secondary corrections, either classes of
-        instances - in case of custom parameters. If dictionary is
-        given, the key must be the name of the correction as defined in
-        secondary.py with a lower first letter.
-    
-    """
-    def __init__(self,corrections:dict={}):
-        for name, obj in inspect.getmembers(secondary):
-            if inspect.isclass(obj):
-                _name = name[0].lower() + name[1:]
-                if type(corrections) is dict:
-                    if _name in corrections:
-                        # instantiation of correction with default values
-                        corr = corrections[_name]
-                        corr = corr() if isinstance(corr,type) else corr
-                        setattr(self,_name,corr)
-                    else:
-                        setattr(self,_name,obj.Dummy())
-                else:
-                    effect_name = obj.__qualname__
-                    setattr(self,_name,obj.Dummy())
-                    # loop for all effects to check if any of the input
-                    # corrections are inner of the available corrections
-                    for corr in corrections:
-                        # instantiation of correction with default values
-                        corr = corr() if isinstance(corr,type) else corr
-                        correction_name = type(corr).__qualname__
-                        if effect_name in correction_name:
-                            setattr(self,_name,corr)
-                            break
-
-
-    def __iter__(self):
-        """Iterate corrections."""
-        for value in self.__dict__.values():
-            yield value
-
-
 class BaseBEM:
     """Base BEM class.
 
@@ -89,7 +40,7 @@ def __init__(self,rotor:rotor.Rotor,rho:float=1.225,corrections:dict=None):
         self.n = len(rotor.sections)
 
         if corrections is None: corrections = {}
-        self.corrections = Corrections(corrections)
+        self.corrections = correction.Corrections(corrections)
         
 
 
diff --git a/bemol/correction.py b/bemol/correction.py
new file mode 100644
index 0000000..dba8939
--- /dev/null
+++ b/bemol/correction.py
@@ -0,0 +1,55 @@
+
+import inspect
+from types import ModuleType
+
+from . import secondary
+
+
+class Corrections(object):
+    """Class for storing corrections.
+
+    Consider all the corrections available in the secondary
+    models module. If not given by the user considers the base (empty)
+    correction with the default parameters.
+
+    Parameters
+    ----------
+    corrections : optional
+        dictionary or list with the secondary corrections, either classes of
+        instances - in case of custom parameters. If dictionary is
+        given, the key must be the name of the correction as defined in
+        secondary.py with a lower first letter.
+    
+    """
+    def __init__(self,corrections:dict={}):
+
+        for name_mod, mod in inspect.getmembers(secondary):
+            if not isinstance(mod,ModuleType): continue
+            effect_name = name_mod[0].lower() + name_mod[1:]
+            for name_obj, obj in inspect.getmembers(mod):
+                if inspect.isclass(obj):
+                    if type(corrections) is dict:
+                        if effect_name in corrections:
+                            # instantiation of correction with default values
+                            corr = corrections[effect_name]
+                            corr = corr() if isinstance(corr,type) else corr
+                            setattr(self,effect_name,corr)
+                        else:
+                            setattr(self,effect_name,mod.Dummy())
+                    else:
+                        setattr(self,effect_name,mod.Dummy())
+                        # loop for all effects to check if any of the input
+                        # corrections are classes of the available corrections
+                        for corr in corrections:
+                            # instantiation of correction with default values
+                            # TODO: check name before instanciating!
+                            corr = corr() if isinstance(corr,type) else corr
+                            if effect_name in corr.__module__:
+                                setattr(self,effect_name,corr)
+                                break
+
+
+    def __iter__(self):
+        """Iterate corrections."""
+        for value in self.__dict__.values():
+            yield value
diff --git a/bemol/secondary.py b/bemol/secondary.py
deleted file mode 100644
index 71bdc64..0000000
--- a/bemol/secondary.py
+++ /dev/null
@@ -1,202 +0,0 @@
-"""
-
-Secondary correction models
-
-"""
-
-import numpy as np
-from . import bem
-
-
-INV_TWO_PI = float(2.0/np.pi)
-
-
-class HubTipLoss:
-
-    class Dummy:
-        """Empty hub/tip loss correction model."""
-
-        def __init__(self) -> None:
-            return
-
-        def __call__(self,*args,**kwargs):
-            return 1.0
-    
-    class Prandtl:
-        """Prandt hub/tip loss correction model.
-        
-        Parameters
-        ----------
-        epsilon: float, optional
-            minimal value of F to avoid errors close to/at the bounds of the
-            blade. Default is 1e-12.
-        
-        """
-        def __init__(self,epsilon=1e-12) -> None:
-            self._epsilon = epsilon
-            return
-
-        def __call__(self,radius,nBlades,hubRadius,tipRadius,inflowAngle):
-
-            fTip = nBlades/2.0*((tipRadius - radius) / (radius*np.abs(np.sin(inflowAngle))))
-            fTip = INV_TWO_PI*np.arccos(np.exp(-fTip))
-
-            fRoot = nBlades/2.0*((radius - hubRadius) / (hubRadius*np.abs(np.sin(inflowAngle))))
-            fRoot = INV_TWO_PI*np.arccos(np.exp(-fRoot))
-
-            return max(fTip*fRoot,self._epsilon)
-
-
-class SkewAngle:
-
-    class Dummy:
-        """Empty skewed wake model."""
-
-        def __init__(self) -> None:
-            return
-
-        def __call__(self,axialInduction,*args,**kwargs):
-            return axialInduction
-    
-    class Burton:
-        """Burton skewed wake model."""
-
-        def __init__(self,) -> None:
-            return
-
-        def __call__(self,axialInduction,yawAngle):
-            return (0.6 * axialInduction + 1.0) * yawAngle
-
-
-class DynamicInflow:
-
-    class Dummy:
-        """Empty dynamic inflow model."""
-
-        def __init__(self) -> None:
-            return
-
-        def __call__(self,axialInduction,*args,**kwargs):
-            return axialInduction
-    
-    class Knudsen:
-        """Knudsen dynamic inflow model."""
-
-        def __init__(self,alphaDynamic=0.3,tauScale=3.0) -> None:
-            self._alpha0 = alphaDynamic
-            self.alphaDynamic = alphaDynamic
-            self.tauScale = tauScale
-
-        def __call__(self,axialInduction,Ux,radius,tStep):
-            if (tStep == 0.):
-                raise ValueError(
-                    f'Using a dynamic inflow model with tStep = {tStep} does not make sense!'
-                    )
-            # lower bound for wind velocity
-            kappa = 1. / (self.tauScale * radius / max(1.0,Ux) )
-            alphaDynamic = tStep*kappa*(axialInduction - self.alphaDynamic) + self.alphaDynamic
-            self.alphaDynamic = alphaDynamic
-
-            return alphaDynamic
-        
-        def restart(self):
-            """Restart alpha to the starting value."""
-            self.alphaDynamic = self._alpha0
-
-
-class YawModel:
-
-    class Dummy:
-        """Empty skewed wake correction model."""
-        
-        def __init__(self) -> None:
-            return
-
-        def __call__(self,axialInduction,*args,**kwargs):
-            return axialInduction
-        
-    class PittAndPeters:
-        """Pitt & Peters skewed wake model.
-        
-        Pitt & Peters 1980, Theoretical prediction of dynamic-inflow derivatives.
-        6th European Rotorcraft & Powered Lift Aircraft Forum 
-        
-        Snel & Schepers 1995, Joint investigation of dynamic inflow effects and
-        implementation of an engineering method. Technical Report ECN-C–94-107,
-        Energy Research Centre of the Netherlands (ECN),
-        publications.ecn.nl/E/1995/ECN-C--94-107
-
-        """
-
-        def __init__(self,factor=15.*np.pi/64.) -> None:
-            self.factor = factor
-        
-        def __call__(self,axialInduction,wakeSkewAngle,azimuthAngle,radius,hubRadius,tipRadius):
-            return axialInduction*(
-                1. + self.factor*np.tan(wakeSkewAngle/2.)*radius/tipRadius*np.sin(azimuthAngle)
-                )
-        
-    class IFPEN:
-        """IFPEN skewed wake model.
-        
-        Blondel et al. 2017, Improving a BEM yaw model based on NewMexico
-        experimental data and Vortex/CFD simulations.
-        CFM 2017 - 23ème Congrès Français de Mécanique
-        ifp.hal.science/hal-01663643 
-        
-        """
-
-        def __init__(self,A0=0.35,Phi1=-np.pi/9,Phi2=np.pi) -> None:
-            self.A0 = A0
-            self.Phi1 = Phi1
-            self.Phi2 = Phi2
-        
-        def __call__(self,axialInduction,wakeSkewAngle,azimuthAngle,radius,hubRadius,tipRadius):
-            k1 = (1 - self.A0) + self.A0*(radius - hubRadius)/(tipRadius - hubRadius)
-            k2 = 1 - self.A0*(radius - hubRadius)/(tipRadius - hubRadius)
-            eta = radius/tipRadius
-            return axialInduction*(
-                1. \
-                + k1*eta*np.tan(wakeSkewAngle/2.)*np.sin(azimuthAngle + self.Phi1) \
-                + k2*(1 - eta)*np.tan(wakeSkewAngle/2.)*np.sin(azimuthAngle + self.Phi2)
-                )
-
-
-class TurbulentWakeState:
-
-    class Dummy:
-        """Empty high-induction correction model.
-        
-        Calls the base thrust coefficient calculation method.
-        """
-        
-        def __init__(self) -> None:
-            return
-
-        def __call__(self,axialInduction,lossFactor,skewAngle,*args,**kwargs):
-            return bem.BaseBEM.CT(axialInduction,lossFactor,skewAngle)
-
-
-    class Buhl:
-        """Buhl's empirical high-induction correction model.
-        
-        TODO: need to find the ref to this method.
-        
-        """
-
-        def __init__(self,beta:float=0.4,da:float=0.02) -> None:
-            self.beta = beta
-            self.da = da
-        
-        def __call__(self,axialInduction,lossFactor,skewAngle):
-            f0 = bem.BaseBEM.CT(self.beta,lossFactor,skewAngle)
-            fp0 = (
-                bem.BaseBEM.CT(self.beta + self.da,lossFactor,skewAngle)
-                - bem.BaseBEM.CT(self.beta - self.da,lossFactor,skewAngle)
-                ) / (2.*self.da)
-            f1 = 2.*np.cos(skewAngle)
-            k2 = (f1-f0-fp0*(1.0 - self.beta)) / (1.0 - self.beta)**2.
-            k1 = fp0 - 2.*k2*self.beta
-            k0 = f1 - k1 - k2
-
-            return k0 + k1*axialInduction + k2*axialInduction**2.
\ No newline at end of file
diff --git a/bemol/secondary/README.md b/bemol/secondary/README.md
new file mode 100644
index 0000000..14c06a9
--- /dev/null
+++ b/bemol/secondary/README.md
@@ -0,0 +1,15 @@
+
+# Secondary correction models
+
+`hubTipLoss.py`: hub/tip loss correction.
+
+`dynamicInflow.py`: dynamic inflow correction.
+
+`skewAngle.py`: skew angle correction.
+
+`turbulentWakeState.py`: turbulent wake state correction.
+
+`yawModel.py`: yaw models.
+
+In order to implement a new model, go to the corresponding file and add
+a new class similar to the ones already present.
\ No newline at end of file
diff --git a/bemol/secondary/__init__.py b/bemol/secondary/__init__.py
new file mode 100644
index 0000000..e4973cf
--- /dev/null
+++ b/bemol/secondary/__init__.py
@@ -0,0 +1,7 @@
+
+
+from . import dynamicInflow
+from . import hubTipLoss
+from . import skewAngle
+from . import turbulentWakeState
+from . import yawModel
diff --git a/bemol/secondary/dynamicInflow.py b/bemol/secondary/dynamicInflow.py
new file mode 100644
index 0000000..9917452
--- /dev/null
+++ b/bemol/secondary/dynamicInflow.py
@@ -0,0 +1,42 @@
+
+
+
+class Dummy:
+    """Empty dynamic inflow model."""
+
+    def __init__(self) -> None:
+        return
+
+    def __call__(self,axialInduction,*args,**kwargs):
+        return axialInduction
+
+
+class Knudsen:
+    """Knudsen dynamic inflow model.
+    
+    T. Knudsen and T. Bak, "Simple model for describing and estimating wind
+    turbine dynamic inflow," 2013 American Control Conference,
+    Washington, DC, USA, 2013, pp. 640-646, doi: 10.1109/ACC.2013.6579909.
+    
+    """
+
+    def __init__(self,alphaDynamic=0.3,tauScale=3.0) -> None:
+        self._alpha0 = alphaDynamic
+        self.alphaDynamic = alphaDynamic
+        self.tauScale = tauScale
+
+    def __call__(self,axialInduction,Ux,radius,tStep):
+        if (tStep == 0.):
+            raise ValueError(
+                f'Using a dynamic inflow model with tStep = {tStep} does not make sense!'
+                )
+        # lower bound for wind velocity
+        kappa = 1. / (self.tauScale * radius / max(1.0,Ux) )
+        alphaDynamic = tStep*kappa*(axialInduction - self.alphaDynamic) + self.alphaDynamic
+        self.alphaDynamic = alphaDynamic
+
+        return alphaDynamic
+    
+    def restart(self):
+        """Restart alpha to the starting value."""
+        self.alphaDynamic = self._alpha0
\ No newline at end of file
diff --git a/bemol/secondary/hubTipLoss.py b/bemol/secondary/hubTipLoss.py
new file mode 100644
index 0000000..6c3a602
--- /dev/null
+++ b/bemol/secondary/hubTipLoss.py
@@ -0,0 +1,42 @@
+
+
+import numpy as np
+
+INV_TWO_PI = float(2.0/np.pi)
+
+
+
+class Dummy:
+    """Empty hub/tip loss correction model."""
+
+    def __init__(self) -> None:
+        return
+
+    def __call__(self,*args,**kwargs):
+        return 1.0
+
+
+class Prandtl:
+    """Prandt hub/tip loss correction model.
+    
+    Parameters
+    ----------
+    epsilon: float, optional
+        minimal value of F to avoid errors close to/at the bounds of the
+        blade. Default is 1e-12.
+    
+    """
+    def __init__(self,epsilon=1e-12) -> None:
+        self._epsilon = epsilon
+        return
+
+    def __call__(self,radius,nBlades,hubRadius,tipRadius,inflowAngle):
+
+        fTip = nBlades/2.0*((tipRadius - radius) / (radius*np.abs(np.sin(inflowAngle))))
+        fTip = INV_TWO_PI*np.arccos(np.exp(-fTip))
+
+        fRoot = nBlades/2.0*((radius - hubRadius) / (hubRadius*np.abs(np.sin(inflowAngle))))
+        fRoot = INV_TWO_PI*np.arccos(np.exp(-fRoot))
+
+        return max(fTip*fRoot,self._epsilon)
+
diff --git a/bemol/secondary/skewAngle.py b/bemol/secondary/skewAngle.py
new file mode 100644
index 0000000..993ffd1
--- /dev/null
+++ b/bemol/secondary/skewAngle.py
@@ -0,0 +1,25 @@
+
+
+class Dummy:
+    """Empty skewed wake model."""
+
+    def __init__(self) -> None:
+        return
+
+    def __call__(self,axialInduction,*args,**kwargs):
+        return axialInduction
+
+
+class Burton:
+    """Burton skewed wake model.
+    
+    Burton "Handbook of wind energy", 2001, page 105.
+
+    """
+
+    def __init__(self,) -> None:
+        return
+
+    def __call__(self,axialInduction,yawAngle):
+        return (0.6 * axialInduction + 1.0) * yawAngle
+
diff --git a/bemol/secondary/turbulentWakeState.py b/bemol/secondary/turbulentWakeState.py
new file mode 100644
index 0000000..7d59c40
--- /dev/null
+++ b/bemol/secondary/turbulentWakeState.py
@@ -0,0 +1,46 @@
+
+
+import numpy as np
+from .. import bem
+
+
+
+
+class Dummy:
+    """Empty high-induction correction model.
+    
+    Calls the base thrust coefficient calculation method.
+    """
+    
+    def __init__(self) -> None:
+        return
+
+    def __call__(self,axialInduction,lossFactor,skewAngle,*args,**kwargs):
+        return bem.BaseBEM.CT(axialInduction,lossFactor,skewAngle)
+
+
+class Buhl:
+    """Buhl's empirical high-induction correction model.
+    
+    Buhl, Jr, M L. "New Empirical Relationship between Thrust Coefficient and
+    Induction Factor for the Turbulent Windmill State.", Aug. 2005.
+    https://doi.org/10.2172/15016819
+    
+    """
+
+    def __init__(self,beta:float=0.4,da:float=0.02) -> None:
+        self.beta = beta
+        self.da = da
+    
+    def __call__(self,axialInduction,lossFactor,skewAngle):
+        f0 = bem.BaseBEM.CT(self.beta,lossFactor,skewAngle)
+        fp0 = (
+            bem.BaseBEM.CT(self.beta + self.da,lossFactor,skewAngle)
+            - bem.BaseBEM.CT(self.beta - self.da,lossFactor,skewAngle)
+            ) / (2.*self.da)
+        f1 = 2.*np.cos(skewAngle)
+        k2 = (f1-f0-fp0*(1.0 - self.beta)) / (1.0 - self.beta)**2.
+        k1 = fp0 - 2.*k2*self.beta
+        k0 = f1 - k1 - k2
+
+        return k0 + k1*axialInduction + k2*axialInduction**2.
\ No newline at end of file
diff --git a/bemol/secondary/yawModel.py b/bemol/secondary/yawModel.py
new file mode 100644
index 0000000..faf80b8
--- /dev/null
+++ b/bemol/secondary/yawModel.py
@@ -0,0 +1,62 @@
+
+import numpy as np
+
+
+
+
+class Dummy:
+    """Empty skewed wake correction model."""
+    
+    def __init__(self) -> None:
+        return
+
+    def __call__(self,axialInduction,*args,**kwargs):
+        return axialInduction
+
+
+class PittAndPeters:
+    """Pitt & Peters skewed wake model.
+    
+    Pitt & Peters 1980, Theoretical prediction of dynamic-inflow derivatives.
+    6th European Rotorcraft & Powered Lift Aircraft Forum 
+    
+    Snel & Schepers 1995, Joint investigation of dynamic inflow effects and
+    implementation of an engineering method. Technical Report ECN-C–94-107,
+    Energy Research Centre of the Netherlands (ECN),
+    publications.ecn.nl/E/1995/ECN-C--94-107
+
+    """
+
+    def __init__(self,factor=15.*np.pi/64.) -> None:
+        self.factor = factor
+    
+    def __call__(self,axialInduction,wakeSkewAngle,azimuthAngle,radius,hubRadius,tipRadius):
+        return axialInduction*(
+            1. + self.factor*np.tan(wakeSkewAngle/2.)*radius/tipRadius*np.sin(azimuthAngle)
+            )
+
+
+class IFPEN:
+    """IFPEN skewed wake model.
+    
+    Blondel et al. 2017, Improving a BEM yaw model based on NewMexico
+    experimental data and Vortex/CFD simulations.
+    CFM 2017 - 23ème Congrès Français de Mécanique
+    ifp.hal.science/hal-01663643 
+    
+    """
+
+    def __init__(self,A0=0.35,Phi1=-np.pi/9,Phi2=np.pi) -> None:
+        self.A0 = A0
+        self.Phi1 = Phi1
+        self.Phi2 = Phi2
+    
+    def __call__(self,axialInduction,wakeSkewAngle,azimuthAngle,radius,hubRadius,tipRadius):
+        k1 = (1 - self.A0) + self.A0*(radius - hubRadius)/(tipRadius - hubRadius)
+        k2 = 1 - self.A0*(radius - hubRadius)/(tipRadius - hubRadius)
+        eta = radius/tipRadius
+        return axialInduction*(
+            1. \
+            + k1*eta*np.tan(wakeSkewAngle/2.)*np.sin(azimuthAngle + self.Phi1) \
+            + k2*(1 - eta)*np.tan(wakeSkewAngle/2.)*np.sin(azimuthAngle + self.Phi2)
+            )
diff --git a/bemol/tools.py b/bemol/tools.py
index 3fdad23..6976db8 100644
--- a/bemol/tools.py
+++ b/bemol/tools.py
@@ -1,7 +1,10 @@
 import numpy as np
 
 
-def calculateVelocity(wind:float,omega:float,rad:float,azi:float,yaw:float,tilt:float,precone:float):
+def calculateVelocity(
+        wind:float,omega:float,rad:float,azi:float,
+        yaw:float,tilt:float,precone:float
+        ):
     """Calculate relative velocity for a given wind configuration
 
     Parameters
diff --git a/environment.yaml b/environment.yaml
index 03cdfdf..a36cd9e 100644
--- a/environment.yaml
+++ b/environment.yaml
@@ -5,7 +5,7 @@ dependencies:
   - python==3.11.2
   - numpy==1.26.4
   - scipy==1.14.1
-  - pandas==2.2.1
+  - pandas==3.0.2
   - pyyaml==6.0.2
-  - matplotlib==3.10.1
+  - matplotlib==3.10.9
   - pytest==8.3.4
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..860d242
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,31 @@
+colorama==0.4.6
+contourpy==1.3.3
+cycler==0.12.1
+exceptiongroup==1.3.1
+fonttools==4.62.1
+iniconfig==2.3.0
+kiwisolver==1.5.0
+matplotlib==3.10.9
+munkres==1.1.4
+numpy==1.26.4
+packaging==26.2
+pandas==3.0.2
+pillow==12.2.0
+pip==26.0.1
+pluggy==1.6.0
+pyparsing==3.3.2
+PySide6==6.11.0
+pytest==8.3.4
+python-dateutil==2.9.0.post0
+pytz==2026.1.post1
+PyYAML==6.0.2
+scipy==1.14.1
+setuptools==82.0.1
+shiboken6==6.11.0
+six==1.17.0
+tomli==2.4.1
+tornado==6.5.5
+typing_extensions==4.15.0
+tzdata==2026.2
+unicodedata2==17.0.1
+wheel==0.47.0
diff --git a/samples/aligned.py b/samples/aligned.py
index 5314b05..72b4163 100644
--- a/samples/aligned.py
+++ b/samples/aligned.py
@@ -26,11 +26,11 @@
 rho = 1.191
 
 corrections = (
-    bemol.secondary.HubTipLoss.Prandtl,
-    bemol.secondary.SkewAngle.Burton,
-    bemol.secondary.YawModel.PittAndPeters,
-    bemol.secondary.DynamicInflow.Dummy,
-    bemol.secondary.TurbulentWakeState.Buhl,
+    bemol.secondary.hubTipLoss.Prandtl,
+    bemol.secondary.skewAngle.Burton,
+    bemol.secondary.yawModel.PittAndPeters,
+    bemol.secondary.dynamicInflow.Dummy,
+    bemol.secondary.turbulentWakeState.Buhl,
     )
 
 # all angles are null, flow completly aligned
diff --git a/samples/iea15mw.py b/samples/iea15mw.py
index 2667b6e..d01f55e 100644
--- a/samples/iea15mw.py
+++ b/samples/iea15mw.py
@@ -28,8 +28,8 @@
 rho = 1.225
 
 corrections = (
-    bemol.secondary.HubTipLoss.Prandtl,
-    bemol.secondary.TurbulentWakeState.Buhl,
+    bemol.secondary.hubTipLoss.Prandtl,
+    bemol.secondary.turbulentWakeState.Buhl,
     )
 
 # all angles are null, flow completly aligned
diff --git a/samples/pitch_maneuver.py b/samples/pitch_maneuver.py
index 3a3acca..21c25b7 100644
--- a/samples/pitch_maneuver.py
+++ b/samples/pitch_maneuver.py
@@ -39,11 +39,11 @@
 mexico = bemol.rotor.mexico
 
 corrections = [
-    bemol.secondary.HubTipLoss.Prandtl,
-    bemol.secondary.SkewAngle.Burton,
-    bemol.secondary.YawModel.Dummy,
-    bemol.secondary.DynamicInflow.Knudsen,
-    bemol.secondary.TurbulentWakeState.Buhl,
+    bemol.secondary.hubTipLoss.Prandtl,
+    bemol.secondary.skewAngle.Burton,
+    bemol.secondary.yawModel.Dummy,
+    bemol.secondary.dynamicInflow.Knudsen,
+    bemol.secondary.turbulentWakeState.Buhl,
 ]
 
 times = np.arange(0.0,50.0,tStep)
diff --git a/samples/yaw.py b/samples/yaw.py
index f29d70c..cfbe58a 100644
--- a/samples/yaw.py
+++ b/samples/yaw.py
@@ -40,9 +40,9 @@
 mexico = bemol.rotor.mexico
 
 corrections = (
-    bemol.secondary.HubTipLoss.Prandtl,
-    bemol.secondary.SkewAngle.Burton,
-    bemol.secondary.TurbulentWakeState.Buhl,
+    bemol.secondary.hubTipLoss.Prandtl,
+    bemol.secondary.skewAngle.Burton,
+    bemol.secondary.turbulentWakeState.Buhl,
     )
 
 
diff --git a/samples/yaw_models.py b/samples/yaw_models.py
index 556b32b..fbdb10b 100644
--- a/samples/yaw_models.py
+++ b/samples/yaw_models.py
@@ -39,9 +39,9 @@
 mexico = bemol.rotor.mexico
 
 base_corrections = [
-    bemol.secondary.HubTipLoss.Prandtl,
-    bemol.secondary.SkewAngle.Burton,
-    bemol.secondary.TurbulentWakeState.Buhl,
+    bemol.secondary.hubTipLoss.Prandtl,
+    bemol.secondary.skewAngle.Burton,
+    bemol.secondary.turbulentWakeState.Buhl,
 ]
 
 
@@ -49,7 +49,7 @@
 for yaw_model in ('Dummy','PittAndPeters','IFPEN'):
 
     corrections = base_corrections.copy()
-    corrections.append(getattr(bemol.secondary.YawModel,yaw_model))
+    corrections.append(getattr(bemol.secondary.yawModel,yaw_model))
 
     solver = bemol.ning.NingUncoupled(mexico,rho,corrections)
     forces, _, azimuths = solver.cycle(
diff --git a/test.py b/test.py
new file mode 100644
index 0000000..08077ab
--- /dev/null
+++ b/test.py
@@ -0,0 +1,12 @@
+
+import bemol
+
+"""Test definition of secondary effects."""
+dummy_rotor = bemol.rotor.mexico
+# model = bemol.bem.BaseBEM(dummy_rotor,corrections={})
+model = bemol.bem.BaseBEM(
+    dummy_rotor,
+    corrections=[
+        bemol.secondary.hubTipLoss.Prandtl,
+        bemol.secondary.skewAngle.Burton
+        ])
\ No newline at end of file
diff --git a/tests/test_result.py b/tests/test_result.py
index 377ccb2..4536630 100644
--- a/tests/test_result.py
+++ b/tests/test_result.py
@@ -32,7 +32,8 @@ def change_test_dir(request,monkeypatch):
 @pytest.fixture(scope='module',autouse=True,)
 def reference_folder(request):
     # define the reference folder based on current folder
-    reference_path = request.config.reference
+    try: reference_path = request.config.reference
+    except AttributeError: return None # doing nothing if reference not given
     return Path( reference_path ).resolve()
 
 
@@ -112,10 +113,13 @@ def test_compare(folder,run,request,reference_folder):
         new_data = pd.read_csv(new_filename)
 
         # only comparing if reference folder available
-        if reference_folder.exists():
+        if reference_folder is not None and reference_folder.exists():
             ref_filename = reference_folder / name_run / filename
             ref_data = pd.read_csv(ref_filename)
-            pd.testing.assert_frame_equal(ref_data,new_data)
+            pd.testing.assert_frame_equal(
+                ref_data,new_data,
+                check_exact=False,rtol=0.0001,
+                )
         else:
             # for the moment just doing nothing if reference folder not
             # available! Make it at least a warning in the future.
diff --git a/tests/test_unit.py b/tests/test_unit.py
index cc7820a..1824bab 100644
--- a/tests/test_unit.py
+++ b/tests/test_unit.py
@@ -18,6 +18,7 @@ def test_airfoil():
     assert airfoil._cl.size > 1
 
 
+
 def test_rotor():
     """Test definition of the rotor class."""
 
@@ -36,7 +37,7 @@ def test_rotor():
 
 
 
-def test_secondary_module():
+def test_secondary_module_default():
     """Test definition of secondary effects."""
     dummy_rotor = bemol.rotor.mexico
 
@@ -49,49 +50,74 @@ def test_secondary_module():
         assert hasattr(model.corrections,'yawModel')
         assert hasattr(model.corrections,'turbulentWakeState')
 
-    # check if the Dummy is selected everytime
+
+
+def test_secondary_module_dummy():
+    """Test if the Dummy is selected everytime"""
+    dummy_rotor = bemol.rotor.mexico
+
     model = bemol.bem.BaseBEM(dummy_rotor)
-    assert model.corrections.hubTipLoss.__class__ is bemol.secondary.HubTipLoss.Dummy
-    assert model.corrections.skewAngle.__class__ is bemol.secondary.SkewAngle.Dummy
-    assert model.corrections.dynamicInflow.__class__ is bemol.secondary.DynamicInflow.Dummy
-    assert model.corrections.yawModel.__class__ is bemol.secondary.YawModel.Dummy
-    assert model.corrections.turbulentWakeState.__class__ is bemol.secondary.TurbulentWakeState.Dummy
+    assert model.corrections.hubTipLoss.__class__ is bemol.secondary.hubTipLoss.Dummy
+    assert model.corrections.skewAngle.__class__ is bemol.secondary.skewAngle.Dummy
+    assert model.corrections.dynamicInflow.__class__ is bemol.secondary.dynamicInflow.Dummy
+    assert model.corrections.yawModel.__class__ is bemol.secondary.yawModel.Dummy
+    assert model.corrections.turbulentWakeState.__class__ is bemol.secondary.turbulentWakeState.Dummy
+
+
+
+def test_secondary_module_custom_list():
+    """Test define a model with a few custom corrections."""
+    dummy_rotor = bemol.rotor.mexico
 
-    # define a model with a few custom corrections
     model = bemol.bem.BaseBEM(
         dummy_rotor,
-        corrections=[bemol.secondary.HubTipLoss.Prandtl,bemol.secondary.SkewAngle.Burton]
+        corrections=[bemol.secondary.hubTipLoss.Prandtl,bemol.secondary.skewAngle.Burton]
         )
-    assert model.corrections.hubTipLoss.__class__ is bemol.secondary.HubTipLoss.Prandtl
-    assert model.corrections.skewAngle.__class__ is bemol.secondary.SkewAngle.Burton
-    assert model.corrections.dynamicInflow.__class__ is bemol.secondary.DynamicInflow.Dummy
-    assert model.corrections.yawModel.__class__ is bemol.secondary.YawModel.Dummy
-    assert model.corrections.turbulentWakeState.__class__ is bemol.secondary.TurbulentWakeState.Dummy
+    assert model.corrections.hubTipLoss.__class__ is bemol.secondary.hubTipLoss.Prandtl
+    assert model.corrections.skewAngle.__class__ is bemol.secondary.skewAngle.Burton
+    assert model.corrections.dynamicInflow.__class__ is bemol.secondary.dynamicInflow.Dummy
+    assert model.corrections.yawModel.__class__ is bemol.secondary.yawModel.Dummy
+    assert model.corrections.turbulentWakeState.__class__ is bemol.secondary.turbulentWakeState.Dummy
+
+
+
+def test_secondary_module_custom_dict():
+    """Same as before, but with dict input define a model with a few custom corrections"""
+    dummy_rotor = bemol.rotor.mexico
 
-    # same as before, but with dict input define a model with a few custom corrections
     model = bemol.bem.BaseBEM(
         dummy_rotor,
         corrections=dict(
-            hubTipLoss=bemol.secondary.HubTipLoss.Prandtl,
-            skewAngle=bemol.secondary.SkewAngle.Burton
+            hubTipLoss=bemol.secondary.hubTipLoss.Prandtl,
+            skewAngle=bemol.secondary.skewAngle.Burton
             )
         )
-    assert model.corrections.hubTipLoss.__class__ is bemol.secondary.HubTipLoss.Prandtl
-    assert model.corrections.skewAngle.__class__ is bemol.secondary.SkewAngle.Burton
-    assert model.corrections.dynamicInflow.__class__ is bemol.secondary.DynamicInflow.Dummy
-    assert model.corrections.yawModel.__class__ is bemol.secondary.YawModel.Dummy
-    assert model.corrections.turbulentWakeState.__class__ is bemol.secondary.TurbulentWakeState.Dummy
-
-    # mix class and instance
-    hub_corr = bemol.secondary.HubTipLoss.Prandtl()
+    assert model.corrections.hubTipLoss.__class__ is bemol.secondary.hubTipLoss.Prandtl
+    assert model.corrections.skewAngle.__class__ is bemol.secondary.skewAngle.Burton
+    assert model.corrections.dynamicInflow.__class__ is bemol.secondary.dynamicInflow.Dummy
+    assert model.corrections.yawModel.__class__ is bemol.secondary.yawModel.Dummy
+    assert model.corrections.turbulentWakeState.__class__ is bemol.secondary.turbulentWakeState.Dummy
+
+
+
+def test_secondary_module_custom_mixed():
+    """Test mix class and instance for correction input."""
+    dummy_rotor = bemol.rotor.mexico
+
+    hub_corr = bemol.secondary.hubTipLoss.Prandtl()
     model = bemol.bem.BaseBEM(
-        dummy_rotor,corrections=[hub_corr,bemol.secondary.SkewAngle.Burton]
+        dummy_rotor,corrections=[hub_corr,bemol.secondary.skewAngle.Burton]
         )
     assert model.corrections.hubTipLoss is hub_corr
-    assert model.corrections.skewAngle.__class__ is bemol.secondary.SkewAngle.Burton
+    assert model.corrections.skewAngle.__class__ is bemol.secondary.skewAngle.Burton
+
 
-    # check if corrections of nested solvers are the same instance
+def test_secondary_module_nested_solvers():
+    """Check if corrections of nested solvers are the same instance."""
     ## TOOD: maybe this is not always the wanted behavior!
+    dummy_rotor = bemol.rotor.mexico
+    corrections = {}
+
     solver_uncoupled = bemol.ning.NingUncoupled(dummy_rotor,1.0,corrections)
     solver_coupled = bemol.ning.NingCoupled(dummy_rotor,1.0,corrections)
     assert solver_coupled.corrections.dynamicInflow is not solver_uncoupled.corrections.dynamicInflow