Accession Number : AD0682329

Title :   REPRESENTATION OF SPACE-TIME VELOCITY AND PRESSURE FLUCTUATION CORRELATIONS BY A TENTATIVE PHENOMENOLOGICAL MODEL,

Corporate Author : STANFORD UNIV CALIF THERMOSCIENCES DIV

Personal Author(s) : Lahey,R. T. , Jr. ; Kline,S. J.

Report Date : AUG 1968

Pagination or Media Count : 44

Abstract : Some difficulties in synthesizing velocity perturbation fields from two-point space-time correlation measurements are discussed including the non-uniqueness of the representation and the effects of averaging. A phenomenological model of the fluctuating velocities based on damped travelling waves has been derived. This model is based on the physical mechanism of slow speed streak 'break-up', as taken from hydrogen bubble visualization data. The model compares quite well with the two-point space-time correlation of velocity perturbations. Furthermore, the form derived for the space-time velocity correlation function is exactly the same form as the best available empirical fit to the space-time wall pressure data. (Author)

Descriptors :   (*FLOW FIELDS, TURBULENT BOUNDARY LAYER), (*TURBULENT BOUNDARY LAYER, MATHEMATICAL MODELS), STATISTICAL FUNCTIONS, CORRELATION TECHNIQUES, PERTURBATION THEORY, BUBBLES, HYDROGEN

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE