# Enhanced Wall function

**URL:** <https://www.simscale.com/forum/t/enhanced-wall-function/81339>\
**Category:** Vote for features!\
**Created:** [December 29, 2017, 10:33am UTC](https://www.simscale.com/forum/t/enhanced-wall-function/81339 "2017-12-29T10:33:02Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![1318980](https://www.simscale.com/forum/user_avatar/www.simscale.com/1318980/32/9637_2.png) [@1318980](https://www.simscale.com/forum/u/1318980)\
**Post date:** [December 29, 2017, 10:33am UTC](https://www.simscale.com/forum/t/enhanced-wall-function/81339/1 "2017-12-29T10:33:02Z")

</div>

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.

Cheers,  
Darren

---

<div class="post-metadata">

**Author:** ![1318980](https://www.simscale.com/forum/user_avatar/www.simscale.com/1318980/32/9637_2.png) [@1318980](https://www.simscale.com/forum/u/1318980)\
**Post date:** [January 2, 2018, 10:27pm UTC](https://www.simscale.com/forum/t/enhanced-wall-function/81339/2 "2018-01-02T22:27:43Z")

</div>

[https://www.openfoam.com/documentation/user-guide/5-models-and-physical-properties/5.1-boundary-conditions](https://www.openfoam.com/documentation/user-guide/5-models-and-physical-properties/5.1-boundary-conditions)