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------------------------------------------------------------
revno: 3674
committer: Raphael Maurin <raph_maurin@xxxxxxxxxxx>
timestamp: Mon 2015-06-08 19:41:35 +0200
message:
  HydroForceEngine: switch averageProfile function into a method
  + modify documentation
modified:
  pkg/common/ForceEngine.hpp


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=== modified file 'pkg/common/ForceEngine.hpp'
--- pkg/common/ForceEngine.hpp	2015-02-06 18:27:58 +0000
+++ pkg/common/ForceEngine.hpp	2015-06-08 17:41:35 +0000
@@ -71,33 +71,36 @@
 
 
 class HydroForceEngine: public PartialEngine{
-	private:
+	public:
 		void averageProfile();
 	public:
 		virtual void action();
-	YADE_CLASS_BASE_DOC_ATTRS(HydroForceEngine,PartialEngine,"Apply drag and lift due to a fluid flow vector (1D) to each sphere + the buoyant weight.\n The applied drag force reads\n\n. math:: F_{d}=\\frac{1}{2} C_d A\\rho^f|\\vec{v_f - v}| vec{v_f - v} \n\n where $\\rho$ is the medium density (:yref:`density<HydroForceEngine.densFluid>`), $v$ is particle's velocity,  $v_f$ is the velocity of the fluid at the particle center,  $A$ is particle projected area (disc), $C_d$ is the drag coefficient. The formulation of the drag coefficient depends on the local particle reynolds number and the solid volume fraction. The formulation of the drag is [Dallavalle1948]_ [RevilBaudard2013]_ with a correction of Richardson-Zaki [Richardson1954]_ to take into account the hindrance effect. This law is classical in sediment transport. It is possible to activate a fluctuation of the drag force for each particle which account for the turbulent fluctuation of the fluid velocity (:yref:`velFluct`). The model implemented for the turbulent velocity fluctuation is a simple discrete random walk which takes as input the reynolds stress tensor Re_{xz} in function of the depth and allows to recover the main property of the fluctuations by imposing <u_x'u_z'> (z) = <Re>(z)/rho^f. It requires as input <Re>(z)/rho^f called :yref:`simplifiedReynoldStresses` in the code. \n The formulation of the lift is taken from [Wiberg1985]_ and is such that : \n\n.. math:: F_{L}=\\frac{1}{2} C_L A\\rho^f((v_f - v)^2{top} - (v_f - v)^2{bottom}) \n\n Where the subscript top and bottom means evaluated at the top (respectively the bottom) of the sphere considered. This formulation of the lift account for the difference of pressure at the top and the bottom of the particle inside a turbulent shear flow. As this formulation is controversial when approaching the threshold of motion [Schmeeckle2007]_ it is possible to desactivate it with the variable :yref:`lift`.\n The buoyancy is taken into account through the buoyant weight : \n\n.. math:: F_{buoyancy}= - rho^f V^p g \n\n, where g is the gravity vector along the vertical, and V^p is the volume of the particle. This engine also evaluate the average particle velocity, solid volume fraction and drag force depth profiles. This is done as the solid volume fraction depth profile is required for the drag calculation, and as the three are required for the independent fluid resolution, and C++ code is faster than python.",
+	YADE_CLASS_BASE_DOC_ATTRS_CTOR_PY(HydroForceEngine,PartialEngine,"Apply drag and lift due to a fluid flow vector (1D) to each sphere + the buoyant weight.\n The applied drag force reads\n\n $F_{d}=\\frac{1}{2} C_d A\\rho^f|\\vec{v_f - v}| vec{v_f - v}$ \n\n where $\\rho$ is the medium density (:yref:`densFluid<HydroForceEngine.densFluid>`), $v$ is particle's velocity,  $v_f$ is the velocity of the fluid at the particle center(:yref:`vxFluid<HydroForceEngine.vxFluid>`),  $A$ is particle projected area (disc), $C_d$ is the drag coefficient. The formulation of the drag coefficient depends on the local particle reynolds number and the solid volume fraction. The formulation of the drag is [Dallavalle1948]_ [RevilBaudard2013]_ with a correction of Richardson-Zaki [Richardson1954]_ to take into account the hindrance effect. This law is classical in sediment transport. It is possible to activate a fluctuation of the drag force for each particle which account for the turbulent fluctuation of the fluid velocity (:yref:`velFluct<HydroForceEngine.velFluct>`). The model implemented for the turbulent velocity fluctuation is a simple discrete random walk which takes as input the Reynolds stress tensor $R^f_{xz}$ as a function of the depth, and allows to recover the main property of the fluctuations by imposing $<u_x'u_z'> (z) = <R^f_{xz}>(z)/\\rho^f$. It requires as input $<R^f_{xz}>(z)/\\rho^f$ called :yref:`simplifiedReynoldStresses<HydroForceEngine.simplifiedReynoldStresses>` in the code. \n The formulation of the lift is taken from [Wiberg1985]_ and is such that : \n\n $F_{L}=\\frac{1}{2} C_L A\\rho^f((v_f - v)^2_{top} - (v_f - v)^2_{bottom})$ \n\n Where the subscript top and bottom means evaluated at the top (respectively the bottom) of the sphere considered. This formulation of the lift account for the difference of pressure at the top and the bottom of the particle inside a turbulent shear flow. As this formulation is controversial when approaching the threshold of motion [Schmeeckle2007]_ it is possible to desactivate it with the variable :yref:`lift<HydroForceEngine.lift>`.\n The buoyancy is taken into account through the buoyant weight : \n\n $F_{buoyancy}= - \\rho^f V^p g$ \n\n, where g is the gravity vector along the vertical, and $V^p$ is the volume of the particle. This engine also evaluate the average particle velocity, solid volume fraction and drag force depth profiles, through the function averageProfile. This is done as the solid volume fraction depth profile is required for the drag calculation, and as the three are required for the independent fluid resolution.",
 		((Real,densFluid,1000,,"Density of the fluid, by default - density of water"))
 		((Real,viscoDyn,1e-3,,"Dynamic viscosity of the fluid, by default - viscosity of water"))
-		((Real,zRef,,,"Position of the reference point which correspond to the first value of the fluid velocity"))
-		((Real,deltaZ,,,"width of the discretization cell "))
-		((Real,expoRZ,3.1,,"Value of the Richardson-Zaki exponent, for the correction due to hindrance"))
+		((Real,zRef,,,"Position of the reference point which correspond to the first value of the fluid velocity, i.e. to the ground."))
+		((Real,deltaZ,,,"Height of the discretization cell."))
+		((Real,expoRZ,3.1,,"Value of the Richardson-Zaki exponent, for the drag correction due to hindrance"))
                 ((bool,lift,false,,"Option to activate or not the evaluation of the lift"))
 		((Real,Cl,0.2,,"Value of the lift coefficient taken from [Wiberg1985]_"))
 		((Real,vCell,,,"Volume of averaging cell"))
-		((int,nCell,,,"number of cell in the height"))
+		((int,nCell,,,"Number of cell in the depth"))
                 ((Vector3r,gravity,Vector3r(0,0,-9.81),,"Gravity vector (may depend on the slope)."))
 		((vector<Real>,vxFluid,,,"Discretized streamwise fluid velocity depth profile"))
-		((vector<Real>,phiPart,,,"Discretized solid volume fraction depth profile"))
-		((vector<Real>,vxPart,,,"Discretized streamwise solid velocity depth profile"))
-                ((vector<Real>,vyPart,,,"Discretized spanwise solid velocity depth profile"))
-                ((vector<Real>,vzPart,,,"Discretized normal solid velocity depth profile"))
-		((vector<Real>,averageDrag,,,"Discretized drag depth profile"))
+		((vector<Real>,phiPart,,,"Discretized solid volume fraction depth profile. Can be taken as input parameter, or evaluated directly inside the engine, calling from python the averageProfile() function, or puting :yref:`activateAverage<HydroForceEngine.activateAverage>` to True."))
+		((vector<Real>,vxPart,,,"Discretized streamwise solid velocity depth profile. Can be taken as input parameter, or evaluated directly inside the engine, calling from python the averageProfile() function, or puting :yref:`activateAverage<HydroForceEngine.activateAverage>` to True."))
+                ((vector<Real>,vyPart,,,"Discretized spanwise solid velocity depth profile. No role in the engine, output parameter. For practical reason, it can be evaluated directly inside the engine, calling from python the averageProfile() method of the engine, or puting :yref:`activateAverage<HydroForceEngine.activateAverage>` to True."))
+                ((vector<Real>,vzPart,,,"Discretized normal solid velocity depth profile. No role in the engine, output parameter. For practical reason, it can be evaluated directly inside the engine, calling from python the averageProfile() method of the engine, or puting :yref:`activateAverage<HydroForceEngine.activateAverage>` to True."))
+		((vector<Real>,averageDrag,,,"Discretized drag depth profile. No role in the engine, output parameter. For practical reason, it can be evaluated directly inside the engine, calling from python the averageProfile() method of the engine, or puting :yref:`activateAverage<HydroForceEngine.activateAverage>` to True."))
 		((bool,activateAverage,false,,"If true, activate the calculation of the average depth profiles of drag, solid volume fraction, and solid velocity for the application of the force (phiPart in hindrance function) and to use in python for the coupling with the fluid."))
-		((bool,velFluct,false,,"If true, activate the determination of turbulent fluid velocity fluctuation for the next time step only at the position of each particle, using a simple discrete random walk model based on the Reynolds stresses :yref:`turbStress<HydroForceEngine.squaredAverageTurbfluct>`"))
-		((vector<Real>,vFluctX,,,"Vector associating a x fluid velocity fluctuation to each particle. Fluctuation calculated in the C++ code"))
-		((vector<Real>,vFluctZ,,,"Vector associating a Z fluid velocity fluctuation to each particle. Fluctuation calculated in the C++ code"))
-		((vector<Real>,simplifiedReynoldStresses,,,"Vector of size equal to :yref:`turbStress<HydroForceEngine.nCell>` containing the Reynolds stresses divided by the fluid density in function of the depth. simplifiedReynoldStresses(z) =  <u_x'u_z'>(z)^2 "))
+		((bool,velFluct,false,,"If true, activate the determination of turbulent fluid velocity fluctuation for the next time step only at the position of each particle, using a simple discrete random walk (DRW) model based on the Reynolds stresses profile (:yref:`simplifiedReynoldStresses<HydroForceEngine.simplifiedReynoldStresses>`)"))
+		((vector<Real>,vFluctX,,,"Vector associating a streamwise fluid velocity fluctuation to each particle. Fluctuation calculated in the C++ code from the discrete random walk model"))
+		((vector<Real>,vFluctZ,,,"Vector associating a normal fluid velocity fluctuation to each particle. Fluctuation calculated in the C++ code from the discrete random walk model"))
+		((vector<Real>,simplifiedReynoldStresses,,,"Vector of size equal to :yref:`nCell<HydroForceEngine.nCell>` containing the Reynolds stresses divided by the fluid density in function of the depth. simplifiedReynoldStresses(z) $=  <u_x'u_z'>(z)^2$"))
 		((Real,bedElevation,,,"Elevation of the bed above which the fluid flow is turbulent and the particles undergo turbulent velocity fluctuation."))
+	,/*ctor*/
+	,/*py*/
+	 .def("averageProfile",&HydroForceEngine::averageProfile,"Compute and store the particle velocity (:yref:`vxPart<HydroForceEngine.vxPart>`, :yref:`vyPart<HydroForceEngine.vyPart>`, :yref:`vzPart<HydroForceEngine.vzPart>`) and solid volume fraction (:yref:`phiPart<HydroForceEngine.phiPart>`) depth profile. For each defined cell z, the k component of the average particle velocity reads: \n\n $<v_k>^z= \\sum_p V^p v_k^p/\\sum_p V^p$,\n\n where the sum is made over the particles contained in the cell, $v_k^p$ is the k component of the velocity associated to particle p, and $V^p$ is the part of the volume of the particle p contained inside the cell. This definition allows to smooth the averaging, and is equivalent to taking into account the center of the particles only when there is a lot of particles in each cell. As for the solid volume fraction, it is evaluated in the same way:  for each defined cell z, it reads: \n\n $<\\phi>^z= \\frac{1}{V_{cell}}\\sum_p V^p$, where $V_{cell}$ is the volume of the cell considered, and $V^p$ is the volume of particle p contained in cell z.\n This function gives depth profiles of average velocity and solid volume fraction, returning the average quantities in each cell of height dz, from the reference horizontal plane at elevation :yref:`zRef<HydroForceEngine.zRef>` (input parameter) until the plane of elevation :yref:`zRef<HydroForceEngine.zRef>`+:yref:`nCell<HydroForceEngine.zRef>`x :yref:`deltaZ<HydroForceEngine.deltaZ>` (input parameters).")
 	);
 };
 REGISTER_SERIALIZABLE(HydroForceEngine);