An Aerodynamic Study of the "Electric Wind"

Citation

Harney, Donald James (1957) An Aerodynamic Study of the "Electric Wind". Engineer's thesis, California Institute of Technology. doi:10.7907/Z774-ZM53. https://resolver.caltech.edu/CaltechETD:etd-04012004-134019

Abstract

The basic physical process considered is the appearance of a pressure gradient in a slightly ionized gas under the influence of an electric field. On a molecular scale this process involves the acceleration of ions in an electric field and the transfer of momentum to the main body of the fluid through collisions. A particular phenomenon involving this basic process is the pressure gradient in a point corona discharge and the resulting "electric wind". The experimental arrangement studied is a point to a downstream coaxial cylinder discharge in air. The difficulity of applying boundary conditions to the mathematical description of the process requires some simplifying assumptions. A simple one-dimensional model of the physical situation is considered, the electrical field equations being approached from the consideration of a space charge limited current. The functional relations derived appear consistent with the experimental results for the limiting cases implied by the assumptions. Velocity variations encountered in the induced flow of air present questions regarding the bulk parameter which describes the molecular interchange of momentum, the ion mobility. While this experiment was not for the purpose of measuring ion mobilities, it is believed that in any applications involving the basic process in the working fluid of the aerodynamicist the time, density, temperature and humidity dependence of the ion mobility requires data which is not now available.

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