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

consistently underestimating lift on a naca 0024 profile.

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 2, 2014, 17:20
Default consistently underestimating lift on a naca 0024 profile.
  #1
New Member
 
Jochem Grietens
Join Date: Nov 2013
Location: Belgium
Posts: 16
Rep Power: 12
JochemGrietens is on a distinguished road
Dear colleagues,

I have been trying to make do a static analysis of a NACA 0024 airfoil in fluent at 5 degrees AoA. But i have consitently been underestimating the Cl. I need to validate the model in this static configuration to move on to a dynamic flapping motion model.

I created the airfoil in solidworks and exported it as a parasolid file. I used ICEM to create a structured grid arround the airfoil and a unstructured grid outside the structured one.

i am working at Re=200.000 with water rho=999.7kg/m³ U=0.866666667m/s and viscosity=0.00129961kg/m-s and chord 0.3m turbulent intensity = 2% turbulent viscosity ratio=10

I am using second order space discretisation with the SIMPLE scheme. As a turbulence model, i use k-omega SST after hybrid initialization (low reynolds number correction not applied).

After modelling i get convergence but i consistantly get an underestimation of the Cl. i get Cl = 0.34208 and Cd = 0.02255 while Airfoiltools tells me that it should be Cl=0.4949 and Cd=0.01732

I have attached the y+ curve along the airfoil edge , it is not around one but i already have a cell heigth of 0.0001m at the airfoil boundary so i don't know if this is where the error get's created.

I have a picture of the mesh in the attachement and the Cl monitor as well as the unscaled residuals.

Does anyone have an idea of what might be going wrong? or something i might try to fix this ?
Attached Images
File Type: jpg yplus.jpg (18.6 KB, 11 views)
File Type: jpg farmesh.jpg (97.4 KB, 8 views)
File Type: jpg meshclose.jpg (44.6 KB, 10 views)
File Type: jpg Cl.jpg (14.1 KB, 8 views)
File Type: jpg unscaled residuals.jpg (18.2 KB, 8 views)
JochemGrietens is offline   Reply With Quote

Reply


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
How to import NACA 0012 Profile in Gridgen maplepink Main CFD Forum 17 May 7, 2013 13:01
Valve lift profile sasanghomi OpenFOAM 2 February 16, 2013 12:56
NACA profile coordinates melwyn rego Main CFD Forum 4 November 21, 2012 06:44
Symmetric NACA Airfoil Lift and Drag Data jrider22 Main CFD Forum 3 April 15, 2010 04:59
bladegen & NACA profile ichgut CFX 1 August 9, 2004 09:31


All times are GMT -4. The time now is 23:33.