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Particle motion in atmospheric boundary layers of Mars and Earth

Authors :
White, B. R
Iversen, J. D
Greeley, R
Pollack, J. B
Publication Year :
1975
Publisher :
United States: NASA Center for Aerospace Information (CASI), 1975.

Abstract

To study the eolian mechanics of saltating particles, both an experimental investigation of the flow field around a model crater in an atmospheric boundary layer wind tunnel and numerical solutions of the two- and three-dimensional equations of motion of a single particle under the influence of a turbulent boundary layer were conducted. Two-dimensional particle motion was calculated for flow near the surfaces of both Earth and Mars. For the case of Earth both a turbulent boundary layer with a viscous sublayer and one without were calculated. For the case of Mars it was only necessary to calculate turbulent boundary layer flow with a laminar sublayer because of the low values of friction Reynolds number; however, it was necessary to include the effects of slip flow on a particle caused by the rarefied Martian atmosphere. In the equations of motion the lift force functions were developed to act on a single particle only in the laminar sublayer or a corresponding small region of high shear near the surface for a fully turbulent boundary layer. The lift force functions were developed from the analytical work by Saffman concerning the lift force acting on a particle in simple shear flow.

Subjects

Subjects :
Lunar And Planetary Exploration

Details

Language :
English
Database :
NASA Technical Reports
Publication Type :
Report
Accession number :
edsnas.19750022907
Document Type :
Report