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| /* This header file can be used to run in Large Eddy Simulation (LES) mode.
By default, the eddy viscosity is based on the Vreman Eddy viscosity model.
In the .c-script, this file should be included after the Navier-Stokes/centered.h
module is included but either before all other events or after the grid
adaptation event.
*/
#include "tracer.h"
#include "diffusion.h"
//#include "Vreman.h"
#include "Dynamic_Smagorinsky.h"
/* Some global variables are initialized, Kh and Km are the diffusivity
for heat and momentum, respectively, Pr is the turbulent Prandlt number,
defined as Pr=Kh−νKm−ν, with ν being the molecular viscosity (molvis),
Csmag is the classical Smagorinsky constant and tracers is a list of
diffusive flow tracers, e.g. the Buoyancy field and total water vapor
field. */
face vector mu_t[]; // turbulent viscosity
scalar Evis[]; // Cell Centered diffusivity
double Csmag;
scalar * tracers;
/* Since Km∝Kh∝Δ2, proper care is required for evaluating corresponding
diffusivities at the different levels of resolution boundaries. */
static inline void Evisprol(Point point,scalar s){
foreach_child()
Evis[]=bilinear(point,Evis)/4.;
}
static inline void Evisres(Point point,scalar s){
double sum = 0.;
foreach_child()
sum += s[];
s[] = sum/2.;
}
/* We set some default values for the parameters that may be overwritten
by the users’ init() event. */
event defaults(i=0){
if (dimension!=3) //Allow to run, but give a warning
fprintf(stdout,"Warning %dD grid. The used formulations only make sense for 3D turbulence simulations\n",dimension);
Csmag=0.12;
Evis.prolongation=Evisprol;
Evis.restriction=Evisres;
/* On tree grids we do not directly care about the diffusivities on
refined and/or coarsend cells and faces. These should be properly
reevaluated before they appear in any computation */
#if TREE
Evis.refine=no_restriction;
Evis.coarsen=no_restriction;
foreach_dimension(){
mu_t.x.coarsen=no_restriction;
}
#endif
}
/* The centered eddyviscosity is evaluated and translated into the
mandadory face-field diffusivity for the usage in other parts of the
solver. */
//event Eddyvis(i++){
// eddyviscosity(Csmag,u,Evis);
// boundary({Evis});
// foreach_face(){
// Km.x[]=(Evis[]+Evis[-1])/2; // Face center
// }
/* In 3D, there are 4 finer faces per coarser face. So consistency
with Km,Kh∝Δ2 is conviniently achieved by applying the Boundary_
flux() function for these face fields */
// boundary_flux({Km});
//}
// overload viscosity event
event viscous_term(i++){
correction (dt); // better approximation of solenoidal velocity field
// compute eddy viscosity
//eddyviscosity(Csmag,u,Evis);
eddyviscosity(u,Evis); // Dynamic Smagorinsky
boundary({Evis});
foreach_face() {
mu_t.x[] = 0.5*(rho[]*Evis[]+rho[-1]*Evis[-1]); // Face center. Multiplied by rho to convert to dynamic viscosity
}
correction (-dt);
boundary_flux({mu_t});
// add to dynamic viscosity
face vector muv = mu;
foreach_face()
muv.x[] = mu.x[] + mu_t.x[];
}
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