From Russia without Valve

[Mike Everman]

That is fantastic! Can you please add the elliptical rotated 90deg?
Then it will be my new screen saver!
I’m particularly fascinated with the interference patterns.

BTW, it will not be detonation, but maybe call it a locus of deflagration.
I’ve always wondered if it helps or hurts to have these waves converging at a point that is the preferred locus of combustion. My acoustic design puts this locus between nodes in the low-order standing waves of the duct.

This is the most interesting visualization in a long time. However, I fear that focusing acoustically like this may be too far different from what the flow needs to do. That is maybe my new reason to want a flat wavefront.

Unless there’s some mixing or other advantage to the velocity and massflow not being perfectly 90deg out of phase???

[AlexanderAndrosov]

Can you please add the elliptical rotated 90deg?

See attachments.
You can create anything you want here:
https://wavesimulator.starfree.app
And, of course, play with different shapes manipulating the waves. This is not the only wave simulator. Google showed me more than one online version, and I believe the more complete versions are for PC.
ANSYS is the most powerful tool I know, but I'm dummy to its extended use.

I’ve always wondered if it helps or hurts to have these waves converging at a point that is the preferred locus of combustion. My acoustic design puts this locus between nodes in the low-order standing waves of the duct.

I assume that the focal point or axis/area (for a circle or cone) as the preferred location will be a high-pressure point to improve mixing and the efficiency of the reaction caused by the compression of air and fuel at one point.
I've seen diesel-powered PJ projects here. I think it will be especially useful here. If diesel is handy at all.
Compression of combustion products into an axis in a cone or sphere will form a kind of cumulative jet from it, as in a projectile, although gas and metal want to fly apart back more. But at some point, this may help to cram more combustion products into the main jet nozzle, which creates the main thrust, to blow through the air inlets and the combustion chamber faster due to the fact that fewer combustion products will go into the first ones. This is my reasoning, which may be incorrect, but otherwise it is advisable to make the focal axis and the axis of the main nozzle coaxial.

By the way, as you can see on the pic you asked, ellipse borns the higher wave lines density near the wall. Maybe that's mean to place the main nozzle(s) radially, not in center, will better ? (just based on visual assumption)
Although a conical nozzle between the combustion chamber and the main pipe will collect everything together.

[Mike Everman]

What is the trick to getting geometry into the wave simulator? I've tried filled geometry and outlined, in jpg and png, gray and black. I just get a blue field.

[AlexanderAndrosov]

What is the trick to getting geometry into the wave simulator? I've tried filled geometry and outlined, in jpg and png, gray and black. I just get a blue field.

I just draw everything I want in any CAD, save it as .png, then use, for example, photoshop's "magic eraser" do delete background.
https://photoshoponline.vn/en/
Maybe your CAD has a button via '"make background transparent" to avoid the second stage. I just didn't find in my one.

I'm used to attaching something, but I don't have anything yet based on my own experience. Therefore, the Soviet VAU-1 type cruise missile "16 Kha"(16Х) is made of a beautiful model kit.

[Mike Everman]

Hmmmmm. Posting does not seem to like .gif, but click on it. Not sure what it's good for.

[AlexanderAndrosov]

It seems to me that you need to increase the resolution and remove the end caps. Otherwise, it turns out that you have a reflection where it shouldn't be.
In any case, compared to serious CAEs like Ansys, it's all a toy, nonsense.