NONEQUILIBRIUM FLOW FIELDS DUE TO SPATIAL PISTON MOTIONS.
Interim scientific rept.
MASSACHUSETTS INST OF TECH CAMBRIDGE AEROPHYSICS LAB
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The inviscid flow resulting from imposing a prescribed piston motion on a gas field previously at rest is examined. The gas model is presumed to possess several energy modes, one of which requires a finite time to approach thermodynamic equilibrium. A unified treatment of planar, cylindrical, and spherical wave motions is formulated by assuming sufficient spatial symmetry to enable description of the field through two independent variables -- distance and time. Emphasis is placed on evaluating, quantitatively as well as qualitatively, the worth of a linearized analysis in predicting the nature of a nonequilibrium flow field. To this end, linear and nonlinear calculations are performed separately and compared. Results indicate that whereas the linear model is successful in the prediction of streamwise events, care must be used in interpreting the predicted flow field normal to the stream. Physical reasons for this dichotomy are discussed. Comparison of the hypersonic flows computed here is made with a recent approximate analytic approach. Author
- Fluid Mechanics
- Reciprocating and Rotating Engines