What is a very weak shock wave? (Gas Dynamics)

[albertov123]

I stumbled upon this concept when studying gas dynamics. What I get from my readings it must occur when Mach number is really close to 1. But I didn't understand how the property relations across a shock wave is affected by it.

 

[boneh3ad]

It's just a shock wave at the limit of $M\rightarrow 1$. Technically the relations don't change but the limit allows you to make approximations to a number of the equations to make them easier to solve.

Alternative, weak can refer to the weak solution to the θ-β-M equation (sometimes δ-β-M or δ-θ-M). The weak solution, in this case, is the one that results in a downstream Mach number greater than 1 and is almost always the solution that physically manifests.