[roberthino]

hi i am new with openfoam. i tried to do a simulation of a turbulent chennel flow (re = 5000) with turb foam and the rng-k-e-model. the channel has a width and height of 0.2m and i chose a length of 2m. i chose 1sec as endtime with timesteps of 1*10e-4s. for lower and upper wall i chose wall function as boundary condition and empty the other two walls. for inlet and outlet i chose cyclic boundary cvondition. my problem is that because of the cyfclic pressure boundary condition i get fluctuations at the beginning and at the end of the channel. the fluctuations are in the pressure distribution and in the Uz-velocity which is that on in the direction of the walls with the wall functions on it. i preffer to have an inlet and outlet boundary condition which is cyclic for the pressure gradient and not for the pressure. maybe someone can tell me how to implement such one.