Analysis of Simple Mechanisms to Continuously Vary Mach Number in a Supersonic Wind Tunnel Facility

Supersonic wind tunnel nozzles are generally capable of producing a constant Mach number flow in the test section of the wind tunnel. As a result, most of the supersonic vehicles are widely designed using steady state flow characteristics which may have errors while facing unsteady situations. This study aims to explore the possibility of varying the Mach number of the flow during wind tunnel operation. The nozzle walls are restricted to be inflexible for cooling near the throat due to high stagnation temperature requirement of the flow to simulate the conditions as experienced by the vehicle. Two simple independent mechanisms, rotation and translation of nozzle walls have been analyzed and the nozzle ranges have been optimized to vary the Mach number from Mach 2 to Mach 5 using minimum number of nozzles in the wind tunnel.

Authors:

• Prateek Kishore
• T. M. Muruganandam

Keywords:

• Method of characteristics
• Nozzle
• supersonic wind tunnel
• variable Mach number.

References:

[1] John Rosen, “The Design and Calibration of a Variable Mach Number Nozzle,” Journal of Aeronautical Sciences, Vol. 22, No. 7, pp. 484-490, 1955.
[2] GUO Shan-guang, WANG Zhen-guo, ZHAO Yu-xin, “Design of a continuously variable Mach-number nozzle”, J. Cent. South Univ, Vol. 22, pp. 522-528, 2015.
[3] H. Winarto and R. J. Stalker, “Design parameters and performance of two-dimensional, asymmetric, ‘sliding block’, variable Mach number, supersonic nozzles
[4] Maurice J. Zucrow, Joe D. Hoffman, “Gas Dynamics, Volume II: Multidimensional flow,” pp. 185-232, 1977
[5] M. Tucker, “Approximate Turbulent Boundary-Layer Development in Plane Compressible Flow Along Thermally Insulated Surfaces with Application to Supersonic-Tunnel Contour Correction”, NACA TN 2045, Mar 1950.