CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Iflation layer and Y+ questions

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   April 21, 2015, 14:44
Default Iflation layer and Y+ questions
New Member
Join Date: Mar 2014
Posts: 19
Rep Power: 5
assafwei is on a distinguished road
Hi all,

I am pretty new to Fluent and recently I bumped into a turbulenece model / meshing conflict.
The company I work for manufactures small products (ranges from 30-200 mm in diameter) with reletively low flows (around 50 m/s, and up t0 200 m/s in very thin regions). These conditions dictates the following to my understanding:

When using k-e model the Y+ should be >30, and this means first layer thickness of about 1mm in my products. I have alot of models with very thin flow regions (going down to the area of 0.1mm thickness) which means I have to mesh the inflation layer with Y+ in the area of 1 (I cannot put big cells there, only small in the order of 0.01mm, or else I will have space for only 1 elements layer)

The main results that I am interested in the solution are bulk, meaning I need the total pressure drop on the system, sum of flow through the inlets / outlets etc.

I can use the k-w model, but with this I have two othr issues / questions:

1. this model requires finer mesh and from what I see needs more time to compute.
2. For the problems I tried, the same model gives better convergence using k-e

And what I am asking myself is - do I really need turbulence modeling? or maybe I can stay with laminar model? if not and if the boundary layer effects the quantities that I am looking for (which are in the bulk as I stated)
is there a workaround that can enable the use of the k-e model with very small cells at the wall?

Thanks for your time.
assafwei is offline   Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
snappyHexMesh Boundary Layer at Corner panpanzhong OpenFOAM Native Meshers: snappyHexMesh and Others 4 October 27, 2014 05:31
SnappyHexMesh - no layer added bejbro OpenFOAM Mesh Utilities 4 October 16, 2014 19:24
Questions about Boundary Layer Thickness and Turbulence Models famerfamer STAR-CCM+ 3 July 12, 2012 09:47
Boundary layer generation problems ivan_cozza OpenFOAM Native Meshers: snappyHexMesh and Others 0 October 6, 2010 13:47
errors Fahad Main CFD Forum 0 March 23, 2004 14:20

All times are GMT -4. The time now is 14:15.