CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

prescribed inflow conditions

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

LinkBack Thread Tools Display Modes
Old   January 29, 1999, 05:35
Default prescribed inflow conditions
Posts: n/a
Hello everybody!

Who could recommend on the prescription of inflow boundary and/or initial conditions for 3D turbulent open-channel flow? Who has made experiences with different conditions? All suggestions in any form (formulas, references etc.) are welcome. Thank you very much in advance for any effort.

Cheers, Thorsten
  Reply With Quote

Old   January 29, 1999, 14:47
Default Re: prescribed inflow conditions
John C. Chien
Posts: n/a
I think, you are talking about the non-uniform inlet condition. There are several approaches: (1). extend the inlet location in the upstream direction, and specify a condition there. ( you hope that when the flow arrives at the real inlet station it will behave in the way you like.) (2). specify the boundary layer thickness, and prescribe the profiels analytically using available data. ( you can control the non-uniform profiles.) ,(3). compute the section of the flow upstream of the inlet separately. ( this way, you have some ideas about the flow at the inlet station.), (4). measure the flow properties at the inlet station and use it in the computation. (if the flow you are going to calculate does not exist , then this method is useless.). I like your question, because this will tell who is the CFD mechanics and who is the CFD engineer. The proper selection of the computational domain and the associated boundary conditions require the real understanding of the problem itself.
  Reply With Quote

Old   January 29, 1999, 16:03
Default Re: prescribed inflow conditions
Posts: n/a
Dear John,

Thanks for your response. Yes you are right possibility No.1 is difficult. I will try a combination of 1. , 2. and 3. first using the logarithmic velocity profile law and having Ushear and Umean computed previously with a 1D calculation. Unfortunately No.4 is not always feasible and very time consuming in addition. I hope this might be worth a try. So thanks again and have a nice day. Best wishes Thorsten
  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
k-w turbulent model and inflow boundary conditions vaina74 Main CFD Forum 6 April 26, 2010 06:03
Inflow turbulence conditions ghost12 Main CFD Forum 0 April 7, 2010 10:09
Turbulent Inflow Conditions ali OpenFOAM Running, Solving & CFD 2 July 9, 2009 09:55
How to set the inflow conditions of turbulent BL? CFDer Main CFD Forum 2 March 8, 2006 10:05
Prescribed inflow velocity profile - how to? Alan Main CFD Forum 10 October 28, 2005 12:14

All times are GMT -4. The time now is 14:04.