Item: Wind Tunnel Blowing Snow Study: Steady and Unsteady Properties of Wind Velocity, Mass Fluxes and Mass Exchanges
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Title: Wind Tunnel Blowing Snow Study: Steady and Unsteady Properties of Wind Velocity, Mass Fluxes and Mass Exchanges
Proceedings: International Snow Science Workshop Grenoble – Chamonix Mont-Blanc - October 07-11, 2013
Authors:
- Mohamed Naaim [ Irstea, UR ETGR, Grenoble, France ]
- Florence NAAIM-BOUVET [ Irstea, UR ETGR, Grenoble, France ]
- Kouichi NISHIMURA [ University of Nagoya, Japan ]
- Osamu ABE [ Shinjo Branch, Snow and Ice Research Center (SIRC), National Research Institute for Earth Science and Disaster Prevention (NIED), Shinjo, Yamagata, Japan ]
- Yoichi ITO [ University of Nagoya, Japan ]
- Masaki NEMOTO [ Shinjo Branch, Snow and Ice Research Center (SIRC), National Research Institute for Earth Science and Disaster Prevention (NIED), Shinjo, Yamagata, Japan ]
- Kenji KOSUGI [ Shinjo Branch, Snow and Ice Research Center (SIRC), National Research Institute for Earth Science and Disaster Prevention (NIED), Shinjo, Yamagata, Japan ]
Date: 2013-10-07
Abstract: Several CFD snow drift models were proposed in the literature. These models include various assumptions and scaling laws representing the mass exchange, the transport and diffusion of particles and the feedback on the air flow. The validations of such existing models were conducted over a partial set of data. This is one of the reasons why we carried out a series of experiments using the low temperature wind tunnel at Shinjo Branch of Snow and Ice Studies (CES : Cryospheric Environment Simulator), NIED in Shinjo, Yamagata Prefecture Japan. The first experiments we undertook allowed to characterize the used snow regarding the wind action. We placed an ultra-sonic anemometer and a snow particle counter at the end of the wind tunnel, and by increasing gradually the wind velocity until the snow entrainment start and we continued until attaining a significant snow fluxes and gradually decreasing the velocity until the transport vanished. We determined the threshold friction velocity. This procedure was conducted twice to evaluate the uncertainty of the determination. Secondly, and for three wind tunnel velocity (5.5 m/s, 7 m/s and 9 m/s) and using a snow depth sensor we measured the mass exchange rate at the base along the flow each 0.5 m and afterwards, we conducted the same experiments by measuring the basal wind velocity and mass fluxes each 1 m from the ground. Finally and at the end of the wind tunnel, where the steady state is clearly attained and using an ultrasonic anemometer and a snow particle counter, we explored the vertical velocity and mass flux evolution. These data are analyzed to explore the macroscopic scaling law relating the mass exchange to the air flow velocity and the mass fluxes and the relation between the horizontal mass flux and the mean velocity. Since these data cover a significant range of flow velocity and include the determination of grain characteristics, the threshold velocity, the erosion fluxes, the air flow and snow fluxes at the interface between the air and the snow at rest, along the flow in the unsteady phase and the vertical snow fluxes and wind velocity profiles in the steady phase, it is a good opportunity to use these data to conduct an international benchmark between available snow drift CFD numerical models.
Object ID: ISSW13_paper_P2-62.pdf
Language of Article: English
Presenter(s): Unknown
Keywords: wind, boundary layer, snow, drifting snow, experimental investigations, saltation, roughness, erosion rate
Page Number(s): 114-119
Subjects: wind velocities snow drifting wind tunnel experiments
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