SimScale CAE Forum

Enhanced Wall function

Boundary layer modelling can effect results dramatically, and in order to get accurate results it is necessary to get as much of the wall in the desired Y+ range. However with problems that have large differences in velocity, or transient simulation where velocity alters over time, this task of re-meshing to get good Y+ values becomes very arduous and often doesn’t bare the required results.

A solution to this would be to create an enhanced wall model which can model the boundary layer all the way from the viscous sub-layer, buffer region and log layer. Taking the example of an air foil, typically getting correct Y+ values over an entire surface is very hard and impossible towards the trailing edge unless the face is split. However, with the above method the wall could have a universally small Y value which can be treated differently depending upon its Y+ if it is anywhere within the boundary layer.

This will reduce the iterative process of meshing to get a good Y+, make good results easier for less experienced users and increase the accuracy of any validation against experimental results.