Výsledky vyhledávání - "James D. Iversen"

Applications of spaceborne radar laboratory data to the study of aeolian processes

Autor: Anthony R. Dobrovolskis, Bruce R. White, Dan G. Blumberg, Stephen D. Wall, Ronald Greeley, Keld Rømer Rasmussen, James D. Iversen, J. F. McHone, Nicholas Lancaster

Publikováno v: Greeley, R, Blumberg, D G, McHone, J F, Dobrovolskis, A, Iversen, J D, Lancaster, N, Rasmussen, K R, Wall, S D & White, B R 1997, ' Applications of spaceborne radar laboratory data to the study of aeolian processes ', Journal of Geophysical Research E: Planets, vol. 102, no. E5, 97JE00518, pp. 10971-10983 . https://doi.org/10.1029/97JE00518

Aerodynamic roughness (z0) is an important parameter in studies of sand and dust transport, as well as atmospheric circulation models. Aerodynamic roughness is a function of the size and spacing of surface roughness elements and is typically determin

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::52f6d9369bf67bf6b67951a6ca3c39f6
https://doi.org/10.1029/97je00518

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Numerical solution of turbulent Taylor-vortex flow

Autor: J.F. Hasiuk, Richard G. Hindman, R.H. Pletcher, James D. Iversen

Publikováno v: Journal of Wind Engineering and Industrial Aerodynamics. 48:13-24

The numerical solution of mean turbulent Taylor-vortex flow is shown. The azimuthal-invariant, cylindrical, Navier-Stokes equations are solved to steady-state for the case of inner cylinder rotation with radius ratio 0.5 and Taylor cell wavelength 2.

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::14019144a7f13e0b54fd269321583d5a
https://doi.org/10.1016/0167-6105(93)90277-u

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The effect of a roughness element on local saltation transport

Autor: Rod N. Leach, James D. Iversen, Jan F. Hasiuk, Keld Rømer Rasmussen, Wen-Ping Wang, Harald Elmo Mikkelsen

Publikováno v: Journal of Wind Engineering and Industrial Aerodynamics. 36:845-854

Wind tunnel tests of rectangular prisms and circular cylinders have been initiated to determine the effects of such boundary layer obstacles on local aeolian saltation erosion and deposition. Preliminary results show that the drift topography adjacen

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::db3a6ca2fb3040694c4bf52d1ce13c7f
https://doi.org/10.1016/0167-6105(90)90081-m

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Some effects of variable porosity and geometry on flow around model barriers

Autor: Janek Hasiuk, James D. Iversen

Publikováno v: Journal of Wind Engineering and Industrial Aerodynamics. 36:509-516

Horizontal velocity and turbulence intensity and pressure were measured in an accelerating turbulent shear flow around model barriers in the wind tunnel. Data were obtained for model barriers with the following porosities and geometries: 25, 50 and 7

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::75cb620d2c5a0ef33bcdfcbff28129aa
https://doi.org/10.1016/0167-6105(90)90334-9

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Dust flux within dust devils: Preliminary laboratory simulations

Autor: Eric E. Eddlemon, Matthew R. Balme, Ronald Greeley, James D. Iversen, Lynn D. V. Neakrase

Publikováno v: Geophysical Research Letters. 33

Laboratory simulations using the Arizona State University Vortex Generator (ASUVG) were run to simulate dust flux in dust devils. These tests used particles 2 μm in diameter and 2600 kg m−3 in density, and the results were compared with data from

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::9a7064615e4fccc5cb00e2cf4d449058
https://doi.org/10.1029/2006gl026810

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The effect of wind speed and bed slope on sand transport

Autor: James D. Iversen, Keld Rømer Rasmussen

Publikováno v: Iversen, J D & Rasmussen, K R 1999, ' The effect of wind speed and bed slope on sand transport ', Sedimentology, vol. 46, no. 4, pp. 723-731 . https://doi.org/10.1046/j.1365-3091.1999.00245.x

This paper reports on a wind tunnel study of the effects of bed slope and wind speed on aeolian mass transport. The use of a sloping wind tunnel has enabled estimation of the friction angle α to be about 40°for saltating particles in the range 170-

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::37e747ec387faeb069a537096054b0c0
https://pure.au.dk/portal/da/publications/the-effect-of-wind-speed-and-bed-slope-on-sand-transport(5b8ea6df-0453-42bb-af11-9269f5029b0d).html

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Potential Transport of Windblown Sand: Influence of Surface Roughness and Assessment with Radar Data

Autor: Ronald Greeley, Lisa R. Gaddis, R. Stephen Saunders, Stephen D. Wall, James D. Iversen, Nicholas Lancaster, Anthony R. Dobrovolskis, Keld Rømer Rasmussen, Bruce R. White, Dan G. Blumberg

Publikováno v: Desert Aeolian Processes ISBN: 9789401065191

The transport of windblown sand is controlled by many factors, including wind regime and sediment supply. Surface roughness at the sub-meter scale is also important because it influences both the threshold conditions for particle entrainment and the

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::ede21b687854c847d36d806ce78e8d9d
https://doi.org/10.1007/978-94-009-0067-7_4

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The effect of surface slope on saltation threshold

Autor: James D. Iversen, Keld Rømer Rasmussen

Publikováno v: IVERSEN, JAMES D & RASMUSSEN, KELD RØMER 1994, ' The effect of surface slope on saltation threshold ', Sedimentology, vol. 41, no. 4, pp. 721-728 . https://doi.org/10.1111/j.1365-3091.1994.tb01419.x

A new wind tunnel has been constructed to study the mass transport properties of wind‐blown sand. This report on the first set of experiments in the new wind tunnel concerns the effect of slope on threshold friction speed. The results of this serie

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d4fb9d716c9499f4f2850d31ef404fa8
https://pure.au.dk/portal/da/publications/the-effect-of-surface-slope-on-saltation-threshold(2355df1a-f502-4caf-bc10-d1670559c326).html

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Assessment of aerodynamic roughness via airborne radar observations

Autor: Anthony R. Dobrovolskis, J.J. van Zyl, S. G. Saunders, Ronald Greeley, James D. Iversen, Howard A. Zebker, L. R. Gaddis, S. D. Wall, Bruce R. White, Keld Rømer Rasmussen, Nicholas Lancaster

Publikováno v: Aeolian Grain Transport ISBN: 9783211822746

The objective of this research is to assess the relationship among measurements of roughness parameters derived from radar backscatter, the wind, and topography on various natural surfaces and to understand the underlying physical causes for the rela

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::f29627d017460e68dd472547f1058895
https://doi.org/10.1007/978-3-7091-6703-8_6

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Roughness element effect on local and universal saltation transport

Autor: W. P. Wang, James D. Iversen, H. E. Mikkelsen, Keld Rømer Rasmussen, R. N. Leach

Publikováno v: Aeolian Grain Transport ISBN: 9783211822746

Experimental results are presented which illustrate the effects of permanent surface obstructions on saltation phenomena. It is shown that the topographic drift geometry and the dimensionless erosion rates of windward erosion associated with cylindri

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::3481968fa480c7d64d1de53c971cad97
https://doi.org/10.1007/978-3-7091-6703-8_5

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