Final Report by - Department of Mechanical and Aerospace ...

2. Experimental Techniques and Methods
2.1. Introduction
As part of the Department of Mechanical and Aeronautical Engineering at the
University of California at Davis, one of our primary research tools is simulation using
wind tunnels. In this way, we can study the emissive conditions present at Owens Lake
by controlling the pertinent variables. R.A. Bagnold developed a technique of studying
the dynamics of desert sands by employing the use of an environmental boundary layer
wind tunnel. In his studies, desert sands were placed in the tunnel and the dynamics of
sand movement studied. This type of tunnel has special characteristics not found in a
traditional aeronautical wind tunnel. The development section is quite long to allow for
the development of a turbulent boundary layer characterized by the roughness of the soil
or sand as present in the atmospheric boundary layer (to establish “fetch”). In a similar
fashion, the Saltation Wind Tunnel at the University of California at Davis is designed to
simulate this same type of flow (Figure 3) and can be used to establish emission rates
with pertinent Owens Lake soils.
After establishing the boundary layer dynamics, the primary focus of this wind
tunnel study is then to match wind conditions with those that occur near the surface in the
Owens Valley. From previous studies, the mechanisms of wind development in the
valley occur due to primarily four mechanisms with North/South winds being the primary
effect. Other effects produce intense storm events through Sierra Waves with large down
drafts. In addition, the meeting of North/South air masses lead to a lee forming
horizontal cyclonic eddy. In the winter, down-valley drainage flow is the predominant
weather pattern; in spring, there is combination of both down-valley drainage and up
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