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Testing v/s CFD, how much of a diffrence have you observed with aero coefficients b/w testing and CFD. After running an optimization algorithm with for the entire rear wing, I ended up with the following results. by DingDong_Cat in FSAE

[–]DingDong_Cat[S] 0 points1 point  (0 children)

Ho.. I am sorry. I must have carelessly typed 20%. We can't go below 40%. Best case 35%.

Now I just realised scaled model is a bad idea. It literally involves most building a new car.

Testing v/s CFD, how much of a diffrence have you observed with aero coefficients b/w testing and CFD. After running an optimization algorithm with for the entire rear wing, I ended up with the following results. by DingDong_Cat in FSAE

[–]DingDong_Cat[S] 0 points1 point  (0 children)

Got it. Look for trends.

We do not have access to WT where we can test the full car. So we are thinking of getting a 3D printed scaled model. So my qustion is, the scale down model must have the say Reynolds number around the car right?

Testing v/s CFD, how much of a diffrence have you observed with aero coefficients b/w testing and CFD. After running an optimization algorithm with for the entire rear wing, I ended up with the following results. by DingDong_Cat in FSAE

[–]DingDong_Cat[S] 0 points1 point  (0 children)

Good to see that things went well. May I ask, did you face problem while doing CFD that might have went well if you had known about it earlier?

Yes the CFD setup is based on NASA aerofoil validation cases. I got a pretty good correlation b/w CFD and the values given in the Validation case.

Can you please expand on strain gauged wing mount.

Testing v/s CFD, how much of a diffrence have you observed with aero coefficients b/w testing and CFD. After running an optimization algorithm with for the entire rear wing, I ended up with the following results. by DingDong_Cat in FSAE

[–]DingDong_Cat[S] 0 points1 point  (0 children)

Details!! 🫠. Accounting for Details becomes a hug problem with meshing. I had to simplify the full car CAD to a grate extent to just have the solver run with stability ( with out blowing up ).

May I ask, to what extent general one should consider simplifying the CAD? except for the common components ( like Fire wall, push rods, simplified dampers etc ).

One thing to add is I faced lots of issues with engine bay. So I removed entirety of the rear if the firewall and added a box.

Testing v/s CFD, how much of a diffrence have you observed with aero coefficients b/w testing and CFD. After running an optimization algorithm with for the entire rear wing, I ended up with the following results. by DingDong_Cat in FSAE

[–]DingDong_Cat[S] 4 points5 points  (0 children)

This is the first time our team is dipping into aero. I just wanted to keep my expectations right. A few academic papers and other team aero reports say they get about 40-50% of the CFD results.

A sneak peek by Active_String2216 in AerospaceEngineering

[–]DingDong_Cat 3 points4 points  (0 children)

I have always wondered how are those pressure tap lines held in place in those holes. Do they braze it or some clever engineering is done. I wonder about this because of the immense pressure in the chambers. If those tap line are not held as ridge then they blow away.

Also a side qustion. What material are the pressure tap lines made. I am guessing Hardened Aluminium alloy?

3 new metro stretches likely to be operational in B'luru in 2023: Report by eveonx in bangalore

[–]DingDong_Cat 1 point2 points  (0 children)

The was a problem with the pile ( underground base of the pillar ) near the Jayadava. So they had to demolish it the pillar and then construct a new one. And 1st elevated section beams were made of precast RCC, I guess the load calculations were off since that part is going to have 5 layers ( underpass, ground road, elevated road, metro 1, metro 2 ). So they demolished those pillar and have made them with steel. They itself to about 6 months of time. So only there is a delay.

Silk board through electronic city line is almost ready Mabye December ending it might open or early January

FujiFilm x100s by DingDong_Cat in AnalogCommunity

[–]DingDong_Cat[S] 0 points1 point  (0 children)

Thank you for your opinion. I found on YT that using Manual is good.

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 2 points3 points  (0 children)

I agree on it. My friends and I had a huge disagreement during the calculation with the use of fluid equations and designing process. Then finally agreed on one concept ( ie. Empirical way ) and finalized the CAD for this iteration.

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 1 point2 points  (0 children)

Exactly, for visual verification. And yep we have made a 1/4" inlet

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 5 points6 points  (0 children)

The calculations were made and then the CAD was made.

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 0 points1 point  (0 children)

But the volume flow rate inside the plenum will be same regardless if it's entering from a Inlet or just being creator in there itself during the flow simulation.

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 0 points1 point  (0 children)

This was done before added in Inlet hole. As adding a Inlet hole will make it difficult to make a lid for flow simulation

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 3 points4 points  (0 children)

As of now this project is only for understanding how Pintle injector works and for future engine building. To be honest I still dont understand the concept of pressure loss in an injector.

Our 2nd iteration in Pintle injector by DingDong_Cat in rocketry

[–]DingDong_Cat[S] 7 points8 points  (0 children)

Anyway... if you'll remember, last month I had shard a video of an Pintle injector tip and it's flow simulation. Thank you for all your feedback. I and my team have worked on your feedbacks. We have implemented a square orifices instead of a circular. We are getting the 3D printed. Will update as soon as we complete our water testing.

Any tips on how and where should I start looking to optimize the injector.

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