
Accession Number : AD0600102
Title : ON HYDRODYNAMIC STABILITY OF TWODIMENSIONAL UNSTEADY INCOMPRESSIBLE LAMINAR BOUNDARY LAYERS.
Corporate Author : NOTRE DAME UNIV IND
Personal Author(s) : Yang,KwangTzu ; Kelleher,Matthew D.
Report Date : FEB 1964
Pagination or Media Count : 101
Abstract : A linearized hydrodynamic stability theory for unsteady incompressible laminar boundary layers over arbitrary cylinders is described. Criteria based on the instantaneous rate of change of the disturbance energy are introduced. In order to apply these criteria to a given unsteady laminar boundarylayer problem, it is necessary to have a complete knowledge of the instantaneous disturbanceamplitude functions. It is found that these disturbanceamplitude functions are governed by a partial differential equation, which can be solved by a numerical iteration scheme. Successive iterations are then obtained by solving an inhomogeneous ordinary differential equation repeatedly at the same time instants. Two numerical examples are calculated. One deals with unsteady flow over a flat plate when the freestream, initially steady, undergoes a stepwise change in its velocity to one and onehalf times of its original value. The second example treats an unsteady stagnation flow with its freestream velocity, initially again steady, undergoing deceleration first and then changing to acceleration.
Descriptors : (*INCOMPRESSIBLE FLOW, BOUNDARY LAYER), (*LAMINAR BOUNDARY LAYER, STABILITY), FLUID DYNAMICS, BOUNDARY VALUE PROBLEMS, THEORY, PARTIAL DIFFERENTIAL EQUATIONS, ITERATIONS, CYLINDRICAL BODIES, FLAT PLATE MODELS, STAGNATION POINT
Distribution Statement : APPROVED FOR PUBLIC RELEASE