The spinning rotor gauge: Measurements of viscosity, velocity slip coefficients, and tangential momentum accommodation coefficients

Tekasakul, Perapong; Bentz, J. A.; Tompson, Robert V.; Loyalka, Sudarshan K.

doi:10.1116/1.580249

Cited by 38 publications

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“…27,29 The introduction of slip boundary conditions into the theory should lead not only to the measurement of the viscosities of gases but also to the measurement of the associated velocity slip and accommodation coefficients. 39,40 …”

Section: Discussionmentioning

confidence: 98%

Rotatory oscillations of arbitrary axi-symmetric bodies in an axi-symmetric viscous flow: Numerical solutions

1998

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The problem of the rotatory oscillation of an axi-symmetric body in an axi-symmetric, viscous, incompressible flow at low Reynolds number has been studied. In contrast to the steady rotation of a body, which involves solving the Laplace equation, the study of an oscillating body requires solution of the Helmholtz equation which results from the simplification of the unsteady Stokes equations. In the present work, we have numerically evaluated the local stresses and torques on a selection of free, oscillating, axi-symmetric bodies in the continuum regime in an axi-symmetric viscous incompressible flow. The Helmholtz equation was solved by a Green’s function technique. The accuracy of the technique is tested against known solutions for a sphere, a prolate spheroid, a thin disk, and an infinitely long cylinder. Good agreements have been obtained. Finite cylinders have been studied and the edge correction factors for the circular disk geometry, that are basic to oscillating disk viscometers, have been calculated. It has been found that the calculated edge correction factors, based on the ratios of the real parts of the actual torques (calculated from this work) to the ideal torques, agree to within 1% to 10% with the reported values obtained by Clark et al. [Physica A 89, 539 (1977)] using the theory of Kestin and Wang [J. Appl. Mech. 24, 197 (1957)]. However, since the ratios of the real parts and the ratios of the imaginary parts of the torques do not coincide, the edge correction factors depend upon which ratio is used.

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Section: Discussionmentioning

confidence: 98%

Rotatory oscillations of arbitrary axi-symmetric bodies in an axi-symmetric viscous flow: Numerical solutions

1998

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“…One of the most notable applications of rotary oscillation of an axi-symmetric body, as stated earlier, is the oscillating disk viscometer. We are planning to extend the work of this paper to viscometer in the near future, and this should facilitate the extraction of the velocity slip and tangential momentum accommodation coe cients also from the data in the same manner as has been accomplished by the use of spinning rotor gauge [32,33].…”

Section: Discussionmentioning

confidence: 99%

Rotary oscillations of axi‐symmetric bodies in an axi‐symmetric viscous flow with slip: Numerical solutions for sphere and spheroids

Tekasakul

Loyalka

2003

Numerical Methods in Fluids

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SUMMARYRotary oscillations of several axi-symmetric bodies in axi-symmetric viscous ows with slip are investigated. A numerical method based on the Green's function technique is used wherein the relevant Helmholtz equation, as obtained from the unsteady Stokes equation, is converted into a surface integral equation. The technique is benchmarked against a known analytical solution, and accurate numerical results for local stress and torque on spheres and spheroids as function of the frequency parameter and the slip coe cients are obtained. It is found that in all cases, slip reduces stress and torque, and increasingly so with the increasing frequency parameter. The method discussed here can be potentially extended to the realistic case of an oscillating disk viscometer.

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“…[10][11][12][13][14] The technique primarily consists of using a SRG to measure the frictional drag induced by a gaseous medium on a freely spinning, magnetically levitated spherical rotor. The rotor is accelerated electrically to a desired rotational speed by a motor head.…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…Viscosities (,ϫ10 7 g cm Ϫ1 s Ϫ1 ), velocity slip coefficients (c m ), and tangential momentum accommodation coefficients ͑␣͒ for He and Ar are shown for the modified SRG using the current absolute measurement method and are compared to the relative values obtained in our previous work 10. …”

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confidence: 98%

Measurements of viscosity, velocity slip coefficients, and tangential momentum accommodation coefficients using a modified spinning rotor gauge

Bentz¹,

Tompson²,

Loyalka³

2001

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The spinning rotor gauge: Measurements of viscosity, velocity slip coefficients, and tangential momentum accommodation coefficients

Cited by 38 publications

References 0 publications

Rotatory oscillations of arbitrary axi-symmetric bodies in an axi-symmetric viscous flow: Numerical solutions

Rotatory oscillations of arbitrary axi-symmetric bodies in an axi-symmetric viscous flow: Numerical solutions

Rotary oscillations of axi‐symmetric bodies in an axi‐symmetric viscous flow with slip: Numerical solutions for sphere and spheroids

Measurements of viscosity, velocity slip coefficients, and tangential momentum accommodation coefficients using a modified spinning rotor gauge

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