CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Turbulence intensity too high on the inlet

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

LinkBack Thread Tools Display Modes
Old   November 5, 2013, 12:07
Default Turbulence intensity too high on the inlet
New Member
Laszlo A.
Join Date: Oct 2013
Location: Bristol, UK
Posts: 4
Blog Entries: 1
Rep Power: 5
trollreign is on a distinguished road
I am a beginner (or more like a restarter) of CFD.
I am modelling atmospheric boundary layer flow, trying to simulate the flow around wind turbines. I set an inlet boundary condition with incoming flow velocity of 10m/s and turbulence intensity of 10%. The model is a 2D top view. The turbines are large (107m diameter), the flow domain is 1500x3000m, the mesh has roughly 70,000 elements (refined around the turbines). The turbines are modelled in this very simple first try as fans with a pressure drop determined from a thrust coefficient of 0.7 on the turbines (or for those familiar with the actuator disk concept an axial induction factor of ~0.3). I am using a k-epsilon model with the standard parameters in Fluent.

The problem I am facing is that even though I set the inlet turbulence intensity between 10-15%, the solution converges, but a contour plot of turbulence intensity shows TI values between 60% and 200% across the simulation domain, including the inlet.

I may be missing something here, but I do not understand where these high TI values are coming from? Must be something with the definition of the k-epsilon model and/or the definition of turbulence intensity and turbulent length scale on the inlet. The length scale I am choosing is anywhere between 10m to 340.2m, I tried several scenarios but in each case the TI is very high.

Any help is appreciated.
trollreign is offline   Reply With Quote


fan boundary condition, k-epsilon model, length scale, turbulence intensity

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
How to define the turbulence intensity and mixing length at an outlet (for k-eps)? david39 OpenFOAM Running, Solving & CFD 6 February 2, 2011 04:01
High turbulence intensity wenfengxie FLUENT 1 April 16, 2010 12:00
High Turbulence Intensity Problem bwg FLUENT 1 January 13, 2010 14:09
Turbulence intensity BC Ralf Schmidt FLUENT 3 June 30, 2006 04:17
Turbulence Intensity Vs CFD Simulation Apple L S Chan Main CFD Forum 3 December 15, 1998 18:28

All times are GMT -4. The time now is 09:11.