|
[Sponsors] |
Lower than expected Coefficient of Lift against angle of attack |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
December 10, 2023, 05:27 |
Lower than expected Coefficient of Lift against angle of attack
|
#1 |
New Member
Gideon Chia
Join Date: Dec 2023
Posts: 2
Rep Power: 0 |
Hi all, for a school project I'm looking at the lift against angle of attack for a 3D NACA 2414 wing at about a Reynold's number of 200,000. However, I am getting results that are about 30% lower than expected compared to an experiment and 2 other CFD studies I found which more or less agree with each other. My apologies for a wall of text but I would greatly appreciate it anyone's help to identify places that may be causing this error. I have attached an imgur link for my screenshots and images: https://imgur.com/a/TL8pADi
1. Mesh Firstly, my wing has a chord of 140mm and a span of 240mm. I am using a C-domain 40 times the chord. For inflation layers, I've set first layer height to be 0.02786mm, 15 maximum layers to get an eventual y+ = 1 (I have been using k-w SST). My edge and face sizing around the wing is 1.4mm and I have a body of influence with 5mm element size. 2. Fluent Pressure-based, steady. I have been using the k-w SST model. However, trying different models (k-e realiable and SA) did not really improve my results. I have opted to use a constant value for air density and viscosity. For my boundary conditions, I will use my 10 degree angle of attack case. My reference values are taken from the inlet. For methods, I used second order upwind. For report definitions I used the vector compotents. And lastly, I intialise from the inlet. 3. Results I get the following results. They are lower than expected vs experimental data at the same Reynold's number and lower than other CFD studies I found. I really would appreciate any input! |
|
December 10, 2023, 11:46 |
|
#2 |
Senior Member
Lorenzo Galieti
Join Date: Mar 2018
Posts: 375
Rep Power: 12 |
Interestingly, you are catching the correct Cl and Cd at 0 AoA. You sure you are not messing up your trigonometry calculations for Vx and Vy?
|
|
December 10, 2023, 11:54 |
|
#3 |
New Member
Gideon Chia
Join Date: Dec 2023
Posts: 2
Rep Power: 0 |
Oh my I hope its as simple as that, but I don't think this was the mistake I made.
Here are the trig numbers I used: https://imgur.com/0ZpRLom |
|
Tags |
coefficient of lift, experimental data |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
How can i get the resonable drag and lift coefficient in fluent? | blivurmind | FLUENT | 0 | September 1, 2020 23:27 |
POSDAT problem | piotka | STAR-CD | 4 | June 12, 2009 09:43 |
Automotive test case | vinz | OpenFOAM Running, Solving & CFD | 98 | October 27, 2008 09:43 |
angle of attack | kiran | FLUENT | 0 | September 10, 2004 09:18 |
Lift Coefficient Vs. Angle of Attack | cfd_pro | Main CFD Forum | 1 | August 23, 2002 18:21 |