Existing linearized theories can not predict cavity flow around a thick hydrofoil. The authors propose a new nonlinear theory for a partially cavitating hydrofoil with arbitrary profile where cavity does not generate from the leading edge of the hydrofoil. Transient cavity flow model is adopted at the present theory. According to Hess and Smith's method for a two-dimensional steady flow, line sources and vortex are distributed on the surface of hydrofoil and that of cavity to solve nonlinear equations derived from following boundary conditions, flow direction is parallel to the surface on wetted portion of the hydrofoil, flow velocity is constant on cavity surface except for the collapsing region, position of cavity tip agrees with laminar separation point or transition point of boundary layer on the cavitating hydrofoil. The solution is derived by an iterative procedure.In the cavity collapsing region, cavity shape and collapsing length are determined by solving Rayleigh's equation for a single spherical bubble and connected to the constant velocity region. The laminar separation point and the transition point are derived from boundary layer calculation. Experiments were made for a hydrofoil with symmetrical section whose chord was 150 mm and thickness was 12 mm. The position of cavity tip and end, cavity shape, pressure distribution and velocity distribution in wake were measured. Drag coefficient was calculated from the wake measurement. The results of present theory were found to be in good agreement with those experimental results.
On application of nonlinear cavity flow theory to thick foil sections
Ueber die Anwendung der nichtlinearen Kavitaetsstroemungstheorie bei dicken Tragflaechenabschnitten
Second Int. Conf. on Cavitation. I Mech E ; 1983-8 ; 167-174
1983
8 Seiten, 14 Bilder, 1 Tabelle, 15 Quellen
Aufsatz (Konferenz)
Englisch
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