Investigation of Effects Caused b y a Pulsed Discharge and a Magnetic Field in a Mach 5 Flow

*† This paper presents an experimental study of the effects of plasmas and magnetic fields on a Mach 5 flow over a flat plate with a half wedge leading edge. The measurement tool used in this investigation is a pitot probe composed of a piezoresistive pressure transducer connected to a short tube which is placed in the flow field . The nice aspect of this pressure transducer is that it is small and can be placed relatively close to the plasma discharge allowing higher speed pitot probe measurements to be made. It is difficult to find small, fast acting transducers that detect very low pressures. The quick est response time that can be discerned with this device is on the order of a few milliseconds. This is faster than the pitot probe measurements that we have made in the past by about two orders of magnitude. One of the reasons for making these measurement s was to investigate the response of the Mach 5 flow to a pla sma discharge that is turned off and on at different frequencies . This was done with and without a magnetic field applied. Electrical noise was a problem in all of the measurements, but it became more of a problem when the magnetic field was applied to the plasma discharge. The results presented in this paper point out that changes in the flow field that result because of the application of a plasma discharge take place in a time frame less than a few milliseconds.