CH10: Similarity Rules Flashcards
What dimensionless terms characterize the Cp in two dimensional axially symmetric flow of a perfect gas.
Cp = f(x/c, M, gamma, t/c)
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What is the main difference between similarity considerations and dimensional analysis?
Dimensional analysis simply lists the dimensionless parameters that are involved, whereas similarity analysis shows how to group these dimensionless quantities in such a way as to reduce the number of independent variables.
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True or False
For linearized equations, it is essential to make a study of similarity in order to gain useful physical results.
False
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What similarity rules exist for two-dimensional linearized flow?
Two members of a family of shapes characterized by the thickness ratios tau1 and tau2 have pressure distributions given by coefficients cp1 and cp2.
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The hypersonic similarity parameter is defined as K = _____.
M_infinity * Tau
Where Tau = is the body thickness ratio.
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True or False
At very high Mach numbers, the mock angle may be of the same order or less than the maximum deflection angle of the body.
True.
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True or False
For large values of the hypersonic parameter, the difference between beta (the shock angle) and mu (the Mach angle) is not important.
False
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In the transonic case, the ______ extend to the field is large and changes________ the direction of the flow are of main importance.
lateral
along
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In the hypersonic regime, the flow field is very ________ , since the shockwaves lie close to the body, and the changes________ To the direction of flow are the most important ones.
narrow
normal
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True or False
In hypersonic flow it is generally not possible to assume irrotational flow, with a corresponding velocity potential.
True.
GD, Roshko, Pg. 265
