Ignore:
Timestamp:
Jun 30, 2020 3:05:20 PM (4 years ago)
Author:
suehring
Message:

Limit logarithmically interpolated particle speed to the velocity component at the first prognostic grid point (since no stability corrected interpolation is employed the particle speed could be overestimated in unstable conditions violating the CFL restriction made for particle speeds)

File:
1 edited

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  • palm/trunk/SOURCE/lagrangian_particle_model_mod.f90

    r4546 r4585  
    2525! -----------------
    2626! $Id$
     27! Limit logarithmically interpolated particle speed to the velocity component
     28! at the first prognostic grid point (since no stability corrected interpolation
     29! is employed the particle speed could be overestimated in unstable conditions).
     30!
     31! 4546 2020-05-24 12:16:41Z raasch
    2732! Variables iran and iran_part completely removed, added I/O of parallel random numbers to restart
    2833! file
     
    37173722!--                as sensitivity studies revealed no significant effect of
    37183723!--                using the neutral solution also for un/stable situations.
     3724!--                However, as the stability correction is missing the particle
     3725!--                speed may be overestimated compared to the velocity component
     3726!--                at the first prognostic grid point. Hence, the particle speed
     3727!--                is limited.
    37193728                   u_int(n) = -usws_int / ( us_int * kappa + 1E-10_wp )        &
    37203729                               * log_z_z0_int - u_gtrans
     3730
     3731                   u_int(n) = SIGN( MIN( ABS( u_int(n) ), ABS( u(k_wall+1,jp,ip) ) ), u_int(n) )
     3732
    37213733                ENDIF
    37223734!
     
    38123824!--                as sensitivity studies revealed no significant effect of
    38133825!--                using the neutral solution also for un/stable situations.
     3826!--                However, as the stability correction is missing the particle
     3827!--                speed may be overestimated compared to the velocity component
     3828!--                at the first prognostic grid point. Hence, the particle speed
     3829!--                is limited.
    38143830                   v_int(n) = -vsws_int / ( us_int * kappa + 1E-10_wp )        &
    38153831                            * log_z_z0_int - v_gtrans
     3832
     3833                   v_int(n) = SIGN( MIN( ABS( v_int(n) ), ABS( v(k_wall+1,jp,ip) ) ), v_int(n) )
    38163834
    38173835                ENDIF
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