CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

Can we model flow over an airplane wing with incompressible flow equations?

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

Like Tree1Likes
  • 1 Post By FMDenaro

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 29, 2019, 03:36
Arrow Can we model flow over an airplane wing with incompressible flow equations?
  #1
Senior Member
 
Join Date: Jan 2018
Posts: 120
Rep Power: 5
Moreza7 is on a distinguished road
Hi,
As you know, airplanes have an average velocity of 750 km/h which means they have a Mach number of about 0.6.
According to NASA:
Quote:
For low speed, or subsonic conditions, the Mach number is less than one, M < 1 and the square of the Mach number is very small. Then the left hand side of the equation is very small, and the change in density is very small. For the low subsonic conditions, compressibility can be ignored.
Does it mean that I can neglect the effect of compressibility and use incompressible equations to simulate the flow over the airfoil using LES or etc?
Is the solution reliable?
How much error can be generated?
Moreza7 is offline   Reply With Quote

Old   June 29, 2019, 03:52
Default
  #2
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 5,772
Rep Power: 61
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by KevinSpears View Post
Hi,
As you know, airplanes have an average velocity of 750 km/h which means they have a Mach number of about 0.6.
According to NASA:

Does it mean that I can neglect the effect of compressibility and use incompressible equations to simulate the flow over the airfoil using LES or etc?
Is the solution reliable?
How much error can be generated?



It depends on the flow problem. Check the inlet Mach condition but consider that the flow accelerate along the airfoil and the Mach can reach higher values. If transonic effects can be disregardable, the incompressible formulation could be quite acceptable. A value of the inlet Mach number greater than 0.3 would address towards a compressible formulation.
Moreza7 likes this.
FMDenaro is offline   Reply With Quote

Reply

Tags
airfoil, airplane, les

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Use of k-epsilon and k-omega Models Jade M Main CFD Forum 39 March 19, 2020 18:27
interFoam wave propagation and explosion of Courant number and residuals ChiaraViola OpenFOAM Running, Solving & CFD 1 June 26, 2019 05:36
difference between incompressible k-epsilon model and compressible k-epsilon model yhy20081016 OpenFOAM Running, Solving & CFD 3 January 19, 2016 07:49
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
Inviscid Drag at subsonic, subcritical Mach # Axel Rohde Main CFD Forum 1 November 19, 2001 12:19


All times are GMT -4. The time now is 00:29.