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Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

1993

University of Pennsylvania

Articles 1 - 2 of 2

Full-Text Articles in Mechanical Engineering

Torsional Sensor Applications In Two-Phase Fluids, Jin O. Kim, Haim H. Bau, Yi Liu, Lawrence C. Lynnworth, Steven A. Lynnworth, Kimberly A. Hall, Saul A. Jacobson, James. A. Korba, Robert J. Murphy, Michael A. Strauch, Kyle G. King Sep 1993

Torsional Sensor Applications In Two-Phase Fluids, Jin O. Kim, Haim H. Bau, Yi Liu, Lawrence C. Lynnworth, Steven A. Lynnworth, Kimberly A. Hall, Saul A. Jacobson, James. A. Korba, Robert J. Murphy, Michael A. Strauch, Kyle G. King

Departmental Papers (MEAM)

A solid corrosion-resistant torsional waveguide of diamond cross section has been developed to sense on-line and in real-time the characteristics of the liquid in which it is submerged. The sensor can measure, among other things, the liquid content of a bubbly medium; the density of adjacent pure liquids; the equivalent density of liquid-vapor mixtures or particulate suspensions; a suspension's concentration; and the liquid level. The sensor exploits the phenomenon that the speed of propagation of a torsional stress wave in a submerged waveguide with a noncircular cross section is inversely proportional to the equivalent density of the liquid in ...


Feedback Control Stabilization Of The No-Motion State Of A Fluid Confined In A Horizontal Porous Layer Heated From Below, Jie Tang, Haim H. Bau Jun 1993

Feedback Control Stabilization Of The No-Motion State Of A Fluid Confined In A Horizontal Porous Layer Heated From Below, Jie Tang, Haim H. Bau

Departmental Papers (MEAM)

We consider a horizontal three-dimensional saturated porous layer, confined in an upright cubic box, heated from below and cooled from above. In the absence of a controller, the fluid maintains a no-motion state for subcritical Rayleigh numbers R < Rc, where Rc, depends on the box’s aspect ratio. Once this critical number is exceeded, fluid motion ensues. We demonstrate that, with the use of feedback control strategies which suppress flow instabilities, one can maintain a stable no-motion state for Rayleigh numbers far exceeding the classical critical one for the onset of convection. To preserve the equilibrium no-motion state of ...