Evaluation of Quasi-Steady Approximation for Viscous Effects in Unsteady Liquid Pipe Flow,
Abstract
Usage of the quasi-steady square law approximation for viscous effects in unsteady one-dimensional turbulent pipe flow is questioned. This approximation which presently is employed in some manner in most unsteady turbulent flow calculations is utilized to compute the attenuation of a pressure wave generated by rapid closure of a down-stream terminal valve in a flow system. It is shown that observed values for viscous attenuation may be several times greater than those obtained utilizing the quasi-steady analysis. The possibility of utilizing a dynamically determined friction factor in the quasi-steady analysis also is investigated and shown to yield inconsistent results. It is concluded that for severe case of unsteadiness associated with pressure surges the quasi-steady approximation is inadequate. Because of significant changes of velocity distributions in most unsteady flow situations the use of a quasi-steady approximation is not supported for unsteady flow calculations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 24, 1968
- Accession Number
- AD0714539
Entities
People
- D. J. Wood
- T. Y. Kao
Organizations
- University of Kentucky