[ { "id": "authors:mxmkf-19n05", "collection": "authors", "collection_id": "mxmkf-19n05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141014-162616524", "type": "monograph", "title": "Experimental Study of Cavitating Hydrofoils in Cascade", "author": [ { "family_name": "Acosta", "given_name": "A. J.", "clpid": "Acosta-A-J" }, { "family_name": "Wade", "given_name": "R. B.", "clpid": "Wade-R-B" } ], "abstract": "Liquid filled hydraulic systems often operate in such a way that cavitation may take place in one or more of the components of the system. Most often the cavitation will take place in a pump or a turbine as the liquid\nvelocity there is usually greatest in these devices. However, cavitation can also occur in bends or elbows or constrictions in the system, such as a venturi tube. When cavitation does take place, the region occupied by the\ncavitation process displaces liquid that was formerly there, creating in a sense a \"reservoir\", the volume of which depends upon the extent of the cavitation. In every case the amount of cavitation in any type of hydraulic\ndevice will increase as the system pressure is lowered. The liquid that has been displaced causes changes in the motion of the fluid throughout the system causing or requiring time-varying pressure gradients to occur. In\nmost practical hydraulic systems in which cavitation can occur, these transient pressure changes die away and the liquid flow system operates about some steady mean value. Indeed, for some applications cavitation is\ndeliberately introduced into the system in such a way as to cause the flowing system to operate at a steady, stable condition.", "publisher": "California Institute of Technology", "publication_date": "1968-02" }, { "id": "authors:g98r1-0qm47", "collection": "authors", "collection_id": "g98r1-0qm47", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150603-114116510", "type": "monograph", "title": "Selectively Ventilated Ring Wing Hydrofoils", "author": [ { "family_name": "Acosta", "given_name": "A. J.", "clpid": "Acosta-A-J" }, { "family_name": "Wade", "given_name": "R. B.", "clpid": "Wade-R-B" } ], "abstract": "Experiments were made on a ring wing having a chord-diameter\nratio of one-half with a profile section consisting of a 10 percent Clark Y airfoil. Measurements were made of the force characteristics of this ring wing in fully wetted flow for several Reynolds numbers and angles of attack; in fully wetted flow these observations agreed\nwith similar previous results on fully wetted ring wings. A portion of the circumference of the ring was also ventilated by the controlled\ninjection of air to provide a cross-force. The magnitude of this cross-force varies with extent of ventilation and with the rate of injection of air. With less than approximately 11 percent of the trailing edge of the wing so ventilated, the cross-force corresponds to the wing in fully wetted flow having an angle of attack of nearly three\ndegrees. Experiments were also made on the rapidity with which this cross-force could be built up at the start of injection or terminated after the ventilation had been established. The termination of the\ncross-force is very quick and amounts to a time approximately required for the flow to travel a distance of a few wing chords. The build-up process on the other hand is considerably slower, and it appears to be a dynamic one but the scaling laws for this phenomenon\nare not yet established.", "publisher": "California Institute of Technology", "publication_date": "1967-08" }, { "id": "authors:bq9zy-ezd31", "collection": "authors", "collection_id": "bq9zy-ezd31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150603-101938906", "type": "monograph", "title": "Experimental Study of the Effects of a Gap Clearance on the Performance of a Fully Cavitating Flat Plate with and without a Flap", "author": [ { "family_name": "Wade", "given_name": "R. B.", "clpid": "Wade-R-B" } ], "abstract": "Experimental results are presented for the effect of a hinge gap on the fully cavitating performance of a flat plate hydrofoil without and with a flap. From the results of the tests it is concluded that for the zero flap deflection, no significant effects of the gap are apparent for the range of the parameters investigated. However, for a 20% flap-to-chord ratio and a 20\u00b0 flap deflection a significant drop occurs in the lift and moment coefficients for a given gap ratio. This effect increases\nwith increase in gap width. The drag on the other hand is unaffected for the range of values tested.\n\nCertain qualitative effects of the jet, arising from the gap, on the cavity appearance are discussed. Comparison of the experimental results for zero gap, with established non-linear theories, show very good agreement.", "publisher": "California Institute of Technology", "publication_date": "1965-11" }, { "id": "authors:5117f-c4466", "collection": "authors", "collection_id": "5117f-c4466", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150604-155316496", "type": "monograph", "title": "Water Tunnel Observations on the Flow Past a Plano-Convex Hydrofoil", "author": [ { "family_name": "Wade", "given_name": "R. B.", "clpid": "Wade-R-B" } ], "abstract": "Experimental results of the performance of a plano-convex\nhydrofoil under non-cavitating and cavitating conditions are presented. Lift, drag and moment coefficients are given as a function of the cavitation number, together with the behavior of the cavity length.\n\nSome unsteady effects occurring under cavitating conditions\nare also considered. In this region of cavitation the magnitude of the force oscillations together with the fluctuation of the cavity length are presented. The frequency of these oscillations and the\ngeneral behavior of the cavity are discussed.", "publisher": "California Institute of Technology", "publication_date": "1964-02" } ]