sounds like a variation of gas turbine in disguise. Any implementation that is cheaper and simpler that existing gas turbines, yet reaches its high efficiency and power/weight ratio would be just great.
>The resulting sudden build-up of pressure in the chamber generates a shock wave
that makes me doubtful about longevity of the engine if the shock wave touches the metal.
Gas turbines actually have varying efficiencies against reciprocating engines, depending on the designs being compared. In the overlap area of small turbines and large pistons, pistons win out significantly in HP per fuel rate. Turbines do have higher power/weight as you say though. This Wave engine's pretty different as it features centrifugal versus axial flow (ironically, the first turbines developed by the US/UK attempted centrifugal designs - the germans gave us our modern axial flow jet engines).
A shock contacting the metal isn't a big deal. A typical jetliner will have a standing shock on the upper surface of its wing during cruise flight, visible if the lighting is just right. With this I doubt there will be significant stresses caused by the pressure gradient because the thing is pretty much a compact and flat disk (short moment arms).
> that makes me doubtful about longevity of the engine if the shock wave touches the metal.
Sure. But what about the common reciprocating engine style. There's a lot of mechanical strain with the pistons being yanked back-and-forth 1000s of times/second not to mention the energy lost in counteracting momentum.
considering the upvote to your comment, there is at least another HN reader who thinks that there are 60K+ rpm reciprocating engines and who don't know what detonation sensor, octane number or cavitation are about... Hope you know your Python better :)
>The resulting sudden build-up of pressure in the chamber generates a shock wave
that makes me doubtful about longevity of the engine if the shock wave touches the metal.