Dual Winglet High School Science Fair Project

Using SimScale Fluid Flow / CFD
1

Hello everyone! I am a high school student working on a science fair project about dual winglet designs for aircraft.

I have run a simulation for the winglet I designed. However, I am not sure if the results are accurate because I don’t really have any reference material to compare them to. These are the conditions I am trying to simulate:

  • angle of attack of 15 degrees
  • speed of 15 m/s
  • chord length of 0.1m
  • kinematic viscosity of 1.426 x 10^-5 m^2/s
  • density of 1.246 kg/m^3

Could someone kindly help verify that I ran my simulation correctly? I am not sure about what the lift and drag coeffcients should look like, so it would be very helpful if someone could verify that my numbers are realistic.

Some other questions I have are:

  1. In initial conditions, should the gauge pressure be set to 0 or 101.325 kPa? The simulation I ran had it set to 0 by default, but I am not sure about how that impacts the results.
  2. What is the significance of the initial velocity condition? In run 1, it was set to 0 m/s, and in run 2, I set it to the same values as the velocity inlet condition (15 m/s at an angle of attack of 15 degrees). Both runs resulted in identical lift and drag coefficients, so I am not sure what the purpose of the initial velocity condition is.
  3. In force plots, are lift and drag just shown as pressure forces in their respective directions?
  4. Is there a way to visualize the vortices at the wingtips? The particle trace feature only seems to show particle motion in two-dimensions, so it doesn’t display the vortices I am looking for.

I would greatly appreciate any help or advice. Thanks in advance!

2

Hello SayanS,
thanks for reaching out to us in the forum.

I’ll try to answer 1 by 1:
1-2 Initial Conditions: With the initial condition you can define the starting conditions of your Simulations. If you, for example, know that most of the fluid domain will have a velocity of 15m/s you can assign this velocity, do achieve quicker results, since your Simulation is closer to the steady-state results, from the start. Therefore it’s good that you got the same results in your run with 0 and 2 m/s since the steady-state result should not depend on the initial condition.

  1. The lift and drag forces act are displayed/calculated in the direction of the Vector you defined within the result control item. (Positive values along the vector direction) Also, not only the pressure forces are being taken into account, but also the forces which result because of the wall shear stress.

  2. You can visualize vorticities by activating the vorticity field function, within the result control items.
    Field Calculations | Result Control | SimScale

I hope I could answer your question

Best regards
Sebastian

3

Hi Sebastian,

Thank you so much for your help! I tried activating the vorticity field function and I got the results I was looking for.