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

Knudsen number, MEMS and CFD

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

LinkBack Thread Tools Display Modes
Old   August 17, 2001, 10:43
Default Knudsen number, MEMS and CFD
Fred Uckfield
Posts: n/a
At Knudsen numbers >> 1 the continuum assumption of CFD breaks down as the flow exhibits particle type behaviour. Does anyone know what Knudsen numbers are typical in MEMS? Have people adapted CFD methods to be MEMS applicable? Have they had to?

Any pointers would be welcome.

  Reply With Quote

Old   August 17, 2001, 11:52
Default Re: Knudsen number, MEMS and CFD
Posts: n/a

I think the answer to your first question is that it varies. It all depends on the size of the channel and the state of the fluid being studied. If you are approaching the non-continuum regime, various people have done work extending continuum equations to this regime by modifying the boundary conditions (i.e. temperature jump and velocity slip at the wall as a function of an "accomodation coefficient").

The answer to the second question is yes. People are doing CFD for MEMS devices. I know that CFD Research Corporation is doing quite a bit of work in this area and has several sofware packages specifically designed to work with MEMS devices. See their web page at
  Reply With Quote

Old   August 17, 2001, 19:04
Default Re: Knudsen number, MEMS and CFD
Fred Uckfield
Posts: n/a

Great answer, thanks. Do you know how exactly fluid thermal variation effects a tailored CFD approach to high Knudsen number simulations?

Cheers Fred.
  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
MEMS modeling codes Mohsen Main CFD Forum 3 August 23, 2004 12:12
CFD in micro fluidics? Ming-Jyh Chern Main CFD Forum 4 November 22, 1999 18:08

All times are GMT -4. The time now is 07:36.