Browsing by Author "Holdhusen, James S."
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Item Model Experiments for the Design of a Sixty Inch Water Tunnel Par III(St. Anthony Falls Hydraulic Laboratory, 1948-09) Holdhusen, James S.A study of the test section for a water tunnel was made at the St. Anthony Falls Hydraulic Laboratory as part of the research program for the design of the proposed 6o-in. water tunnel of the David Taylor Model Basin, Bureau of Ships, Department of the Navy. It was determined that the variation in velocity across the test stream would be less than one per cent everywhere except in the boundary layer, which would have a maximum thickness of ten per cent of the diameter of the test section. The pressure gradient and energy loss in the test section were computed assuming the test section boundary layer to be analogous to that of a plate in a uniform stream. The critical cavitation area in the tunnel circuit was found to be at the transition from the test section to the diffuser, and the corresponding critical cavitation indexes were calculated for several points in the test section.Item Model Experiments for the Design of a Sixty Inch Water Tunnel Par IV(St. Anthony Falls Hydraulic Laboratory, 1948-09) Holdhusen, James S.A study of the main diffuser (the diffuser following the test section) for a water tunnel was made at the St. Anthony Falls Hydraulic Laboratory as part of the research program for the design of the proposed 60-in. water tunnel of the David Taylor Model Basin, Bureau of Ships, Department of the Navy. The diffuser was designed on the basis of previous investigations of other experimenters, and the testing program was conducted to determine the action of the diffuser as it will be affected by the conditions of inflow and outflow in the recirculating system of the prototype water tunnel. It was determined that the diffuser will operate satisfactorily as to energy loss but that there will be slight maldistribution of velocity at the downstream end. It was decided, however, that this maldistribution will not be sufficiently detrimental to operation of the water tunnel to warrant making the diffuser longer and of a smaller angle of divergence.Item Model Experiments for the Design of a Sixty Inch Water Tunnel Part II(St. Anthony Falls Hydraulic Laboratory, 1948-09) Ripken, John F.; Holdhusen, James S.A recirculating type of water tunnel is designed to produce a steady stream of fluid having uniform velocity and pressure in the test section. However, the tendency of the recirculating system is to produce variations in velocity from point to point across a section of flow due to growth of the boundary layer. Superimposed on this variation of velocity in space is a variation of velocity in time caused by turbulence in the stream. The necessity of diverting the stream through 360 degrees and of adding energy by means of a rotary impeller introduces the possibility of superposition of steady large-scale turbulence on the stream, but correct design of elbows and pump can effectively eliminate this source of velocity variation.Item Model Experiments for the Design of a Sixty Inch Water Tunnel Part V(St. Anthony Falls Hydraulic Laboratory, 1948-09) Holdhusen, James S.; Lamb, Owen P.A study of vaned elbows was made at the St. Anthony Falls Hydraulic Laboratory as part of the research program for the design of the proposed 60-in. water tunnel of the David Taylor Model Basin, Bureau of Ships, Department of the Navy. The shape, size, and spacing of the vanes to be used in the elbows were determined from the work of previous investigators, and model studies of the vane cascade were performed at the Laboratory as part of a broad research program in fluid flow diversion. Additional model studies of the assembled elbow were performed on a 1:10 scale model of the 6o-in. tunnel. From the model studies on the vane cascade, the optimum angular setting of the vanes was obtained, as well as data regarding pressure distribution and energy loss. The validity of the application of model results to a prototype was examined in the additional studies on the elbows in the model water tunnel. On the basis of this study, a cascade of vanes of the proportions shown in Fig. 44 of this report is recommended for use in the prototype tunnel. The vanes are to be used at a spacing-chord ratio of 0.48 and a stagger angle of 99 to 101 degrees. The miter line is to cross each vane at about 37 1/2 per cent of the chord from the leading edge. Structural analysis of these vanes indicates that they may be of either solid or hollow cross section without detrimental effects on stresses, deflections, or vibrations. The studies also indicate that the vaned elbows in the prototype tunnel will be free from cavitation.Item Model Experiments for the Design of a Sixty Inch Water Tunnel Part VI(St. Anthony Falls Hydraulic Laboratory, 1948-09) Holdhusen, James S.The purpose of the recirculating pump in the water tunnel is to supply energy efficiently to the circulating stream so that the resistance of the circuit may be overcome. In most pump installations this is practically the only requirement for which the pump is designed, but in the water tunnel installation the secondary characteristics of the pump must be carefully controlled. Some of these secondary characteristics which would seriously affect the usability of the water tunnel are pulsation, cavitation, noise level, stream rotation, and outflow velocity maldistribution. This study will not discuss the pump design since that will be the responsibility of the eventual manufacturer. Rather, it will furnish fundamental information based on the tests of the model water tunnel which the manufacturer should know in order to design the pump properly.Item Model Studies for the Design of Open- or Closed-Jet Water Tunnel(St. Anthony Falls Hydraulic Laboratory, 1950-06) Holdhusen, James S.In order to execute an experimental analysis of a proposed 24-in. water tunnel designed at the David Taylor Model Basin [l}*, a 1:4-scale model was constructed and tested at the St. Anthony Falls Hydraulic Laboratory of the University of Minnesota. This model was essentially a modified form of the l:l0-scale model of a 60-in. water tunnel previously tested at the St. Anthony Falls Hydraulic Laboratory. The main modifications were made between the downstream end of the contraction and the elbow leading into the pump assembly; the remaining part of the tunnel circuit was modified only by a change in the length of the 18-in. connecting conduit.