Blow-through, and suction-type is considered as a supersonic wind tunnel. Here are their advantages and disadvantages:
| Supersonic Wind Tunnel | Advantages | Disadvantages |
| Blow-through Tunnel | Lower cost High Mach capability Good design for propulsion and smoke visualization Starts easily No need for high power | Short running time Limited air flow Stagnant temperature and pressure vary due to the air in the reservoir Generates noise during operation |
| Suction Type Tunnel | Stagnation conditions stay constant at atmospheric value High-pressure ratios are easily attained High Mach numbers can be obtained | Short running time Possible poor flow quality High operating cost because of constant fan movement |
Principle: Supersonic working sections are always rectangular in cross section
there are a number of reasons why supersonic working sections are always rectangular in cross section. The first reason is that if the section is rectangular, the construction of nozzles of the required area distribution is easier. Second, there is an involvement of the insertion of plane windows in the side walls of the working section when the visualization of the flow by optical methods is done. Lastly, the model generates shockwave when these are mounted in the working section and tested.
Furthermore, the tunnel walls inevitably reflect these shocks, and it is important that the model should not be struck by the reflected shocks. Due to this reason, the working section must have a minimum height in relation to the model length at any Mach number which is why having a circular section would be impossible for the whole span of two-dimensional model.