code_saturne User's Forum

Hi,
 
I'm trying to calculate the skin friction coefficient for the 2d wall mounted hump which i'm running in 3D for a DDES simulation.
I've run into a few problems calculating the du/dy term. This is how i'm trying to calculate it. This is a section from my usproj.F file.
Any help would be most appreciated.
 
IMOM = 1
IPCMOM = IPPROC(ICMOME(IMOM))
IDTCM = − IDTMOM(IMOM)
UAVG = PROPCE(IEL,IPCMOM) /
MAX (DTCMOM(IDTCM),EPZERO)
 
IMOM = 2
IPCMOM = IPPROC(ICMOME(IMOM))
IDTCM = − IDTMOM(IMOM
VAVG = PROPCE(IEL,IPCMOM) /
MAX (DTCMOM(IDTCM),EPZERO)
 
IMOM = 3
IPCMOM = IPPROC(ICMOME(IMOM))
IDTCM = − IDTMOM(IMOM)
WAVG = PROPCE(IEL,IPCMOM) /
MAX (DTCMOM(IDTCM),EPZERO)
 
DISTBF = RA(IDISTB-1+IFAC)
SRFBNF = RA(ISRFBN-1+IFAC)
UNORM = ( UAVG * SURFBO( 1 ,IFAC)/SRFBNF) +( VAVG * SURFBO( 2 ,IFAC)/SRFBNF)  +( WAVG * SURFBO( 3 ,IFAC)/SRFBNF)
UTAN  =  SQRT ( SQRT (UAVG ** 2 + VAVG ** 2 + WAVG ** 2 ) − UNORM)
 
CF = (VISCLO(1)*UTAN/DISTBF)/(0.5D0*UREF(1)**2)
 
I seem to get a value around 10 times higher than i should do. I'm not sure if I'm using the correct method.
Thanks very much
Neil

hi Niel,
 
sorry for late reply.... u can check this link ... i m sure u would get know how to calculate skin frinction in CS
 
https://code-saturne.info/products/code-saturne/forums/general-usage/335742422

Hi Mubashir,
Thanks for your reply, I managed to solve it after looking again at some vector maths and the user manual, but thanks very much for the link.
Neil