CFD of Drone Downwash does not look Right

Project Support
1

Hello All!

I am working on a custom drone shroud and was hoping to get some help with the simulation as it is not looking correct to me and I have tried a lot.

The air velocity seems to spread out immediately and unnaturally away from the rotors instead of going straight down. I have tried this with both a fan model (200 and 300Pa pressure change) and an average velocity (20m/s) model.

I am really at a loss here, if anyone has any hypotheses or can tell me if I have set up my simulation incorrectly, I would really appreciate it.

I cannot seem to make my projects public (it is an academic account) so unfortunately I cannot share the project links, but I will share as much information as I can below and I am happy to provide more if need be.

What I Expect: (from the internet)

image
image470×307 25.6 KB

What I get: (Showing air speed velocity magnitude)

image
image979×605 55.2 KB

image
image964×579 54 KB

image
image940×934 60.2 KB

image
image1079×858 313 KB

image
image2933×1097 161 KB

image
image462×986 24 KB

image
image1338×555 25.3 KB

image
image452×253 7.69 KB

3

Hi @Andrewb1230

Would it be possible for you to share the project with support? and if possible also guide me to the paper. It is a little bit hard to analyze purely based on just the pictures in this case.

Thanks!
Bryan

4

Hello Bryan!

Yes I shared the projects with support.

I have tried a few more different things now and still it does not look right. I feel I should see a constant velocity coming out of each of the rotors, but I do not at all. I have tried adjusting the thickness of the rotor discs and changing the flow region boundary conditions around, to no avail.

Please let me know what you think.

Andrew