STATIC PERFORMANCE ANALYSIS AT ZERO PITCH ANGLE OF A GROUND EFFECT MACHINE WITH VARIABLE HEIGHT NOZZLES
Abstract
The static performance at zero pitch angle of a three-dimensional ground effect machine having variable-height peripheral nozzles is investigated on the basis of thick jet theory. The machine considered in the analysis is symmetricABOUT ITS LONGITUDINAL CENTERLINE. The side nozzles of constant height are joined by the forward and aft nozzles of variable height (arched). As a result of different nozzle angles in addition to variable height, the ratio of nozzle height/thickness is no longer constant as approximately required by balanced operation of the peripheral jet at the equilibrium or design height. The analysis predicts the configuration of the jet curtain for off-equilibrium-height operation and then obtains the resultant base pressure underneath the machine from the momentum balance of the jets and the continuity of cross mass flow. An iteration procedure for obtaining the base pressure versus height solution is outlined. Relations for discharge and horsepower requirements are then given in terms of the obtained base pressure. The method developed is used to compute the characteristics of the Bureau of Ships Hydroskimmer and the results of these computations are presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1962
- Accession Number
- AD0275044
Entities
People
- J.d. Lin