Open Access
Particle motion in atmospheric boundary layers of Mars and Earth
Bruce R. White,James D. Iversen,Ronald Greeley,James B. Pollack +3 more
- Vol. 75, pp 30980
TLDR
In this article, 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.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.read more
Citations
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Journal ArticleDOI
The particle size of martian aeolian dunes
TL;DR: In this article, the effective particle size of unconsolidated materials on the Martian surface can be determined from thermal inertia, due to a pore size dependence of thermal conductivity at Martian atmospheric pressures.
Journal ArticleDOI
Aeolian behavior of dust in a simulated Martian environment
TL;DR: In this paper, the behavior of aeolian dust, particles 1-2 microns (μm) in diameter, was analyzed in a simulated Martian environment, and the results indicated that the dust never reached fluid saltation threshold because individual particles less than 10 μm typically do not saltate, but pass into suspension.
Journal ArticleDOI
Resuspension of particles from a horizontal surface
J. Tadmor,I. Zur +1 more
TL;DR: In this article, the profile of particle concentration following resuspension was calculated, using basic transport equations, in a computerized model describing the ressuspension process, considering the forces which act upon the discrete particles in a turbulent flow.
DissertationDOI
Wind shielding analysis for cold regions using experimental and numerical techniques
TL;DR: In this paper, the authors present a survey of the literature on the use of POROUS FENCES in cold regions of the United States, focusing on the following: 1 1.1.
References
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Book
Boundary layer theory
TL;DR: The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part, denoted as turbulence as discussed by the authors, and the actual flow is very different from that of the Poiseuille flow.
Book
The Physics of Blown Sand and Desert Dunes
TL;DR: The physics of blown sand and desert dunes, The physics of windblown sand and sand dunes, this paper, and the physics of dunes in the Middle East and Africa.
Journal ArticleDOI
The lift on a small sphere in a slow shear flow
TL;DR: In this article, it was shown that a sphere moving through a very viscous liquid with velocity V relative to a uniform simple shear, the translation velocity being parallel to the streamlines and measured relative to streamline through the centre, experiences a lift force 81·2μVa2k½/v½ + smaller terms perpendicular to the flow direction, which acts to deflect the particle towards the streamline moving in the direction opposite to V.
Journal ArticleDOI
The structure of turbulent boundary layers
TL;DR: In this article, the authors describe the formation of low-speed streaks in the region very near the wall, which interact with the outer portions of the flow through a process of gradual lift-up, then sudden oscillation, bursting, and ejection.
Journal ArticleDOI
An investigation of particle trajectories in two-phase flow systems
S. A. Morsi,A. J. Alexander +1 more
TL;DR: In this article, the authors describe a theoretical investigation into the response of a spherical particle to a one-dimensional fluid flow, and the motion of the spherical particle in a uniform 2D fluid flow about a circular cylinder.