printout velocity derivatives near a wall

peter schaffarczyk

dear collegues, since some years we are using FLUENT among other CFD tools. now we have a problem that we want to have all the velocity derivatives (in fact: cf) near a wall. we tried to implement it as DEFINE_ON_DEMAND UDF. so far all worked ok (coordinates as well as velocities were printed out) But when adding C_DUDX, C_DUDY etc to our subroutine we produced "Segmentation violation". this ususlly indecates that something is wrong with the pointer ( i have admit that i'am a FORTRAN(90)-dino)

does anybody have had related problems or better some practical idea how to overcome out problem?

all we want is just cf_X and cf_y of a specified wall into a file

best wishes and thanks in advance peter schaffarczyk