The distribution of velocity and energy of saltating sand grains in a wind tunnel

Zou, Xueyong; Wang, Zhoulong; Hao, Qingzhen; Zhang, Chunlai; Liu, Yuzhang; Dong, Guangrong

doi:10.1016/s0169-555x(00)00038-6

Cited by 116 publications

(121 citation statements)

References 24 publications

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“…(2) fits well to the observed data with R 2 z 0.94. Wind tunnel experiments by Zou et al (2001) also show that the increase in the velocity of windblown sand particles with height can be expressed by a power function. The difference between their results and ours is that their results focus on resultant particle velocity, whereas ours concern mean downwind velocity.…”

Section: Variations Of the Mean Downwind Velocity Of A Blowing Sand Cmentioning

confidence: 95%

“…There are complex mass and energy exchanges among saltating grains, grains on the surface, and the airflow. Moreover, there are processes difficult to consider in theoretical models such as the Magnus effect and Saffman lifting force (White and Schulz, 1977;Zou et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Although high-speed multi-flash photography and photoelectric cell methods have been used to measure movement velocities of individual particles (Zou et al, 1994;Greeley et al, 1996), these methods prove to be only good for fairly large particles (Greeley and Iversen, 1985). It is also difficult from photographic images to interpret the velocity of sand particles at very low heights such as below 0.5 cm where the grains are too crowded, and at higher height, such as over 7 cm, where the moving grains are too few (Zou et al, 2001). Because a blowing sand cloud is group movement composed of a large number of randomly interacting sand particles with various velocities (e.g., White and Schulz, 1977), the statistical average of particle velocities should be obtained using a sufficient number of sand particles.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of the concentration profile of a blowing sand cloud

Dong

2004

Geomorphology

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Section: Variations Of the Mean Downwind Velocity Of A Blowing Sand Cmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of the concentration profile of a blowing sand cloud

Dong

2004

Geomorphology

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“…The sand movement in a saltation cloud is very complex. Sand velocity is a key factor in studying the vertical distribution of its kinetic energy, which determines the variation of abrasion intensity with height (e.g., Sharp, 1964;Suzuki and Takahashi, 1981;Greeley and Iversen, 1985;Anderson, 1986;Zou et al, 2001;Dong et al, 2004a). Hence, the sand velocity is an important parameter in the study of sand transport by wind.…”

Section: Introductionmentioning

confidence: 99%

Wind tunnel experimental investigation of sand velocity in aeolian sand transport

Kang

Guo

et al. 2008

Geomorphology

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Sand velocity in aeolian sand transport was measured using the laser Doppler technique of PDPA (Phase Doppler Particle Analyzer) in a wind tunnel. The sand velocity profile, probability distribution of particle velocity, particle velocity fluctuation and particle turbulence were analyzed in detail. The experimental results verified that the sand horizontal velocity profile can be expressed by a logarithmic function above 0.01 m, while a deviation occurs below 0.01 m. The mean vertical velocity of grains generally ranges from −0.2 m/s to 0.2 m/s, and is downward at the lower height, upward at the higher height. The probability distributions of the horizontal velocity of ascending and descending particles have a typical peak and are right-skewed at a height of 4 mm in the lower part of saltation layer. The vertical profile of the horizontal RMS velocity fluctuation of particles shows a single peak. The horizontal RMS velocity fluctuation of sand particles is generally larger than the vertical RMS velocity fluctuation. The RMS velocity fluctuations of grains in both horizontal and vertical directions increase with wind velocity. The particle turbulence intensity decreases with height. The present investigation is helpful in understanding the sand movement mechanism in windblown sand transport and also provides a reference for the study of blowing sand velocity.

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“…Most observations of sand movement on a bed surface are from high-speed photography in a wind tunnel (e.g., Mitha et al, 1986;Willetts and Rice, 1986;Rice et al, 1995Rice et al, , 1996Nalpanis et al, 1993). In general, the grain-bed collision process is difficult to measure directly from the high-speed photography because the grains are crowded at the very low height (e.g., Nalpanis et al, 1993;Zou et al, 2001). But recently, by using the advanced high-speed CMOS camera with very high frame rate of 2000 fps, Zhang et al (2007a,b) captured the trajectories and velocities of sand grains in the region very close to the ground surface at the lower free-stream wind velocity (less than 10 m/s).…”

Section: Introductionmentioning

confidence: 99%

Reconstructing the vertical distribution of the aeolian saltation mass flux based on the probability distribution of lift-off velocity

2008

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The probability distribution of lift-off velocity of the saltating grains is a bridge to linking microscopic and macroscopic research of aeolian sand transport. The lift-off parameters of saltating grains (i.e., the horizontal and vertical lift-off velocities, resultant lift-off velocity, and lift-off angle) in a wind tunnel are measured by using a Phase Doppler Particle Analyzer (PDPA). The experimental results show that the probability distribution of horizontal lift-off velocity of saltating particles on a bed surface is a normal function, and that of vertical lift-off velocity is an exponential function. The probability distribution of resultant lift-off velocity of saltating grains can be expressed as a log-normal function, and that of lift-off angle complies with an exponential function. A numerical model for the vertical distribution of aeolian mass flux based on the probability distribution of lift-off velocity is established. The simulation gives a sand mass flux distribution which is consistent with the field data of Namikas (Namikas, S.L., 2003. Field measurement and numerical modelling of aeolian mass flux distributions on a sandy beach, Sedimentology 50, 303-326). Therefore, these findings are helpful to further understand the probability characteristics of lift-off grains in aeolian sand transport.

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The distribution of velocity and energy of saltating sand grains in a wind tunnel

Cited by 116 publications

References 24 publications

Experimental investigation of the concentration profile of a blowing sand cloud

Experimental investigation of the concentration profile of a blowing sand cloud

Wind tunnel experimental investigation of sand velocity in aeolian sand transport

Reconstructing the vertical distribution of the aeolian saltation mass flux based on the probability distribution of lift-off velocity

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