Accession Number : AD0486892

Title :   THE EFFECTIVENESS OF TWO DIMENSIONAL MOMENTUM TRAPS.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV BERKELEY COLL OF ENGINEERING

Personal Author(s) : Su, Chih-Lan ; Willis, D. Roger

Report Date : JUN 1966

Pagination or Media Count : 32

Abstract : When investigating the interchange of momentum between molecules and surfaces by the torsion balance method it is frequently desirable to simulate a surface producing completely diffuse re-emission. To achieve this the use of momentum traps, where the incident molecules enter a region bounded by a concave surface and interreflect many times before re-emission, has been proposed. We analyze the effectiveness of two-edimensional traps having cylindrical, trapezoidal, rectangular and triangular cross-sections. Assuming that the interior surfaces behave effectively as diffusely reflecting surfaces, we solve the resulting Clausing integral equation analytically for the cylinder and numerically for the other geometries. Results are presented for a wide range of the ratio of the depth of the trap to the width of the opening. All geometries result in an enhanced reflected normal mementum flux compared to a diffuse surface covering the opening. The triangular and rectangular traps appear least well suited to simulate completely diffuse reflection. (Author)

Descriptors :   (*RAREFIED GAS DYNAMICS, MOLECULAR BEAMS), MOMENTUM, INTEGRAL EQUATIONS, BALANCES, MOLECULAR PROPERTIES, MOLECULES, SIMULATION, INTEGRAL TRANSFORMS, TWO DIMENSIONAL FLOW.

Subject Categories : Fluid Mechanics
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE