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Article
A Horizontal Vane Radiometer: Experiment, Theory, and Simulation
Physics of Fluids
(2016)
Abstract
The existence of two motive forces on a Crookes radiometer has complicated the investigation of either force independently. The thermal creep shear force in particular has been subject to differing interpretations of the direction in which it acts and its order of magnitude. In this article, we provide a horizontal vane radiometer design which isolates the thermal creep shear force. The horizontal vane radiometer is explored through experiment, kinetic theory, and the Direct Simulation Monte Carlo (DSMC) method. The qualitative agreement between the three methods of investigation is good except for a dependence of the force on the width of the vane even when the temperature gradient is narrower than the vane which is present in the DSMC method results but not in the theory. The experimental results qualitatively resemble the theory in this regard. The quantitative agreement between the three methods of investigation is better than an order of magnitude in the cases examined. The theory is closer to the experimental values for narrow vanes and the simulations are closer to the experimental values for the wide vanes. We find that the thermal creep force acts from the hot side to the cold side of the vane. We also find the peak in the radiometer’s angular speed as a function of pressure is explained as much by the behavior of the drag force as by the behavior of the thermal creep force.
Disciplines
Publication Date
2016
DOI
10.1063/1.4943543
Publisher Statement
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
The article appeared in Physics of Fluids 28, 037103 (2016) and may be found at
http://dx.doi.org/10.1063/1.4943543
Citation Information
David Wolfe, Andres Larraza and Alejandro Garcia. "A Horizontal Vane Radiometer: Experiment, Theory, and Simulation" Physics of Fluids Vol. 28 Iss. 3 (2016) ISSN: 1070-6631 Available at: http://works.bepress.com/alejandro_garcia1/96/