Changeset 4640

Timestamp:

Aug 11, 2020 4:28:32 PM (4 years ago)

Author:

suehring

Message:

synthetic turbulence generator: to avoid that the correction term in r11/r22 computation becomes unrealistically high, limit Obukhov length (term is not valid for near neutral conditions); to avoid unrealistically large perturbations, change computation of r21 so that this resembles the vertical transport of horizontal momentum

File:

• palm/trunk/SOURCE/synthetic_turbulence_generator_mod.f90 (modified) (5 diffs)

palm/trunk/SOURCE/synthetic_turbulence_generator_mod.f90

@@ -25 +25 @@
 ! -----------------
 ! $Id$
+! - to avoid that the correction term in r11/r22 computation becomes unrealistically high, limit 
+!   Obukhov length (term is not valid for near neutral conditions)
+! - to avoid unrealistically large perturbations, change computation of r21 so that this resembles
+!   the vertical transport of horizontal momentum
+!
+! 4629 2020-07-29 09:37:56Z raasch
 ! support for MPI Fortran77 interface (mpif.h) removed
 !
@@ -2130 +2136 @@
                                        )**( 2.0_wp / 3.0_wp ),                                     &
                           0.0_wp,                                                                  &
-                          scale_l < 0.0_wp )
+                          scale_l < -5.0_wp )
 !
 !--    Determine normalized height coordinate
@@ -2144 +2150 @@
        r22(k) = ABS( - sin_phi(k) * rlon1 + cos_phi(k) * rlat1 )
 !
-!--    For u'v' no parametrization exist so far - ?. For simplicity assume a similar profile as
-!--    for u'w'.
-       r21(k) = 0.5_wp * ( r11(k) + r22(k) )
-!
 !--    w'w'
        r33(k) = scale_wm**2 * (                                                                    &
@@ -2164 +2166 @@
        r32(k) = SIGN( ABS( - sin_phi(k) * rlon2 + cos_phi(k) * rlat2 ),                            &
                    - ( v_init(k+1) - v_init(k-1) ) )
+!
+!--    For u'v' no parametrization exist so far. For simplicity assume a similar profile as
+!--    for the vertical transport.
+       r21(k) = 0.5_wp * ( r31(k) + r32(k) )
 !
 !--    Compute turbulent time scales according to Brost et al. (1982). Note, time scales are
@@ -2217 +2223 @@
        r31(k) = r31_zi * blend
        r32(k) = r32_zi * blend
-       r21(k) = 0.5_wp * ( r11(k) + r22(k) )
+       r21(k) = 0.5_wp * ( r31(k) + r32(k) )
 
 !