added factor for ou correlation time

cpp/full_code/ornstein_uhlenbeck_process.cpp

@@ -16,6 +16,7 @@ ornstein_uhlenbeck_process<rnumber,be>::ornstein_uhlenbeck_process(
     double ou_kmin,
     double ou_kmax,
     double ou_energy_amplitude,
+    double ou_gamma_factor,
     double DKX,
     double DKY,
     double DKZ,
@@ -44,6 +45,7 @@ ornstein_uhlenbeck_process<rnumber,be>::ornstein_uhlenbeck_process(
     this->ou_kmin_squ = pow(ou_kmin,2);
     this->ou_kmax_squ = pow(ou_kmax,2);
     this->ou_energy_amplitude = ou_energy_amplitude;
+    this->ou_gamma_factor = ou_gamma_factor;
     this->epsilon = pow((this->ou_energy_amplitude/this->kolmogorov_constant), 3./2.);
 
     assert(this->kk->kM2 >= this->ou_kmax_squ);

cpp/full_code/ornstein_uhlenbeck_process.hpp

@@ -19,6 +19,7 @@ class ornstein_uhlenbeck_process{
         double ou_kmin_squ;
         double ou_kmax_squ;
         double ou_energy_amplitude;
+        double ou_gamma_factor;
         double kolmogorov_constant = 2;
         double epsilon;
 
@@ -38,6 +39,7 @@ class ornstein_uhlenbeck_process{
             double ou_kmin,
             double ou_kmax,
             double ou_energy_amplitude,
+            double ou_gamma_factor,
             double DKX = 1.0,
             double DKY = 1.0,
             double DKZ = 1.0,
@@ -52,7 +54,7 @@ class ornstein_uhlenbeck_process{
 
         inline double gamma(double kabs)
         {
-            return pow(kabs,2./3.)*this->kolmogorov_constant*sqrt(this->kolmogorov_constant/
+            return this->ou_gamma_factor*pow(kabs,2./3.)*this->kolmogorov_constant*sqrt(this->kolmogorov_constant/
                            this->ou_energy_amplitude);
         }
         

cpp/full_code/ou_vorticity_equation.hpp

@@ -24,6 +24,7 @@ class ou_vorticity_equation : public vorticity_equation<rnumber, be>
         double ou_kmin,
         double ou_kmax,
         double ou_energy_amplitude,
+        double ou_gamma_factor,
         double DKX = 1.0,
         double DKY = 1.0,
         double DKZ = 1.0,
@@ -34,7 +35,7 @@ class ou_vorticity_equation : public vorticity_equation<rnumber, be>
               this->ou = new ornstein_uhlenbeck_process<rnumber,be>(
                 NAME,
                 nx, ny, nz,
-                ou_kmin, ou_kmax, ou_energy_amplitude,
+                ou_kmin, ou_kmax, ou_energy_amplitude,ou_gamma_factor,
                 DKX, DKY, DKZ, FFTW_PLAN_RIGOR);
               this->ou_forcing_type = "replace";
             }