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

LSR (Land speed record) car simulation on FLUENT

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 27, 2013, 16:17
Default LSR (Land speed record) car simulation on FLUENT
  #1
New Member
 
Maxime
Join Date: Apr 2013
Posts: 5
Rep Power: 4
Maxime31850 is on a distinguished road
Hi,

I'm a student who is doing analysis concerning a wheel driven Land Speed Record car. I've received the datas concerning the maximum speed that the car can reach, which is 460 mph.

I am using the software ANSYS v14.0 to draw, mesh the geometry and I'm using an old version of FLUENT to run the 3D simulations.
The geometry is quite simple, it is without the wheel.

Concerning the FLUENT simulation, I've encountered some problems .

As I said on the top of this post, the maximum speed of the car will be 460mph, which means that the type of flow is compressible ( Mach Number = 0,6 >0,3).

As a consequence, I cannot use the same boundary entities like for a incompressible flow. I used then Pressure Far Field for the right and left side (as pressure far field inlet and pressure far field outlet) and on the top (pressure far field top).

The problem is that when I tried to run the simulation on FLUENT, the residuals never converged or when I change some parameters some errors appeared.


Here are the parameters I've set in FLUENT for my last simulation :

Define : Models : energy equation : Ok
viscous model : k-epsilon model (standard)
Materials : air : ideal gas from the density
Operating conditions : 0 for the gauge pressure
Boundary conditions : gauge pressure : 101325 Pa
mach number : 0,6
x component flow direction : -1
Turbulence : turbulent viscosity ratio
5% and 5 for the ratio


After that in the tab Solve : I initialize from Pressure far field inlet and run the simulation.

I think the residuals don't converged because of the parameters but I don't really exactly know what do I have to put.
Could you give me some advices concerning them ?

Thank you very much
Maxime31850 is offline   Reply With Quote

Old   April 30, 2013, 06:13
Default
  #2
Member
 
Join Date: Jun 2012
Posts: 32
Rep Power: 5
DonQuijote is on a distinguished road
Hi Maxime.

I haven't done any compressible analysis in Fluent, but did you check your mesh? Did you make sure that it is fine enough in the important zones? Mesh is usually one of the main reasons of non-convergence.

I can't help you about BC, but have you tried to change them (i.e. making the top wall as 'wall')?

Regards
DonQuijote is offline   Reply With Quote

Old   May 1, 2013, 11:15
Default
  #3
New Member
 
Maxime
Join Date: Apr 2013
Posts: 5
Rep Power: 4
Maxime31850 is on a distinguished road
Hi,
firstly thank you for answering.
Regarding the mesh, I have done a face sizing by selecting all the faces from the car and I have done an inflation around it.

About the inflation, in ANSYS, I have chosen in the tab inflation option total thickness and I put 30 boundary layers with a growth rate of 1.2.

I put one inflation too on the road, in order to have accuracy results concerning the ground effect with less boundary layers than around the car.

Do you think these parameters sound good? When I check the Y+ on FLUENT, I have got one located between 50 and 500.
Maxime31850 is offline   Reply With Quote

Reply

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
HELP - Moving car simulation in fluent Brad Wells FLUENT 6 February 27, 2012 03:14
Racing car simulation Edu FLUENT 5 October 16, 2009 11:36
Fluent simulation over airships Aragon FLUENT 0 March 27, 2009 13:38
Can Fluent start a simulation from a negative time Ted Chu FLUENT 10 November 26, 2008 22:06
Car aerodynamics simulation (Pls help, urgent)! Wang FLUENT 1 February 23, 2007 17:06


All times are GMT -4. The time now is 11:27.