0002846: Inconsistent wall BC while using RANS/LES wall functions

ID	Project	Category	View Status	Date Submitted	Last Update

0002846	OpenFOAM	Bug	public	2018-02-14 22:24	2018-02-16 23:11

Reporter	tnnandi	Assigned To	henry
Priority	high	Severity	major	Reproducibility	always
Status	closed	Resolution	unable to reproduce
Platform	GNU/Linux	OS	Ubuntu	OS Version	14.10

Summary	0002846: Inconsistent wall BC while using RANS/LES wall functions
Description	Several tutorials using wallfunctions with RANS/LES turbulence models use no-slip BC for U (fixedValue with value uniform (0 0 0)). This is perhaps not correct, as these wall functions have been developed for cases where the first cell-center adjacent to the wall to be outside the viscous sublayer. This requirement contradicts the no-slip condition (which can only be used if the flow is calculated upto the viscous sublayer). For example, in the windAroundBuildings tutorial, the near-wall eddy viscosity is calculated using the nutkWallFunction. Apart from the eddy viscosity, the wall velocity is also required directly to calculate the terms which involve velocity gradient calculation (e.g. convection and diffusion terms) for the cells adjacent to the wall. Other tutorials with similar BCs are cavity and airfoil2D Fixing the value of velocity to (0 0 0) at the wall may interfere with the velocity gradient calculation for the cells on the wall.
Tags	No tags attached.

Date Modified	Username	Field	Change
2018-02-14 22:24	tnnandi	New Issue
2018-02-14 22:58	henry	Note Added: 0009320
2018-02-16 23:11	henry	Assigned To	=> henry
2018-02-16 23:11	henry	Status	new => closed
2018-02-16 23:11	henry	Resolution	open => unable to reproduce

henry 2018-02-14 22:58 manager ~0009320	Please provide detailed evidence for your hypothesis and an alternative implementation which demonstrates the need for the change and that at least all of the tutorial cases are not adversely affected by it and forces are calculated correctly.