Wave-generated disturbance downstream of a nozzle array

Waves resulting from the expansion process are an important source of nonhomogeneity in the supersonic flow downstream of nozzle arrays. Flows from radial nozzles are analyzed by a small-perturbation procedure that yields the first solutions for the near field in the two-dimensional case and for the entire field in three dimensions. Good agreement is found with method-of-characteristics calculations and with earlier interferometric measurements of integrated density disturbance. The complete solutions bring out the dependence of flow quality on nozzle dimension, Mach number, expansion angle, and ratio of specific heats. Application to laser cavity flow is discussed.