Fluid Dynamics and Circular Plate

4863 WordsJan 14, 201420 Pages
R. & M. No. 3120 (19,958) A.R.C. TechnicalReport MINISTRY OF SUPPLY AERONAUTICAL RESEARCH COUNCIL REPORTS AND MEMORANDA Low-Speed-Experiments. on the Wake Characteristics o f Flat Plates normal to an Air Stream R. FAIL,j. A. LAWFORD and R. C. W. EY~E © Crown copyrigAtx959 LONDON: HER MAJESTY'S STATIONERY OFFICE I959 PRICE IO$. 6d. NET .f Low-Speed Experiments on the Wake Characteristics of Flat Plates normal to an Air Stream R. FaIT., j. A. LAWFORD and R. C. W. EYRE COMMUNICATED BY THE DIRECToR-GENERAL OF SCIENTIFIC RESEARCH (AIR), MINISTI~Y OF SUPPLY Reports and Memoranda No. 312 o* June, 1957 Summary.--Experiments on isolated fiat plates perpendicular to the wind are described. It…show more content…
Vertical movements were obtained by means of a length of streamlined rod clamped to the sliding block. The pitot-tubes and static-tubes were kept parallel to the tunnel axis. Measurements of the velocity near the axis of the plate were made with a pitot-static tube attached to the c e n t r a l rod, 0.6 in. from the axis of the plate. Reverse velocities were measured with this instrument pointing downstream. The hot wire was kept normal to the tunnel axis. The associated electronic equipment which !included a vibration analyser was basically that described in Refs. 4 and 5. 3. Velocity Measuremertts.--3.1. Mean Velocities.--Since the pitot-tubes and static-tubes were set parallel to, and the hot wire normal to the free stream, the velocity measurements are in error where the local stream is not parallel to the free stream. For the particular pitot-tubes and static-tubes used in these experiments, a check showed that the measured velocity exceeded tile ±rue velocity by 2 per cent for 10 deg misalignment and 6 p e r cent for 20 deg misalignment. Angular errors are small near the axis of the bubble and also near the p.osition ,of i t s m a x i m u m width, s'o that the length and m a x i m u m diameter of the bubble are accurately determined. * On the circular plate sufficient snrface-pressur6 measurementswere made (Fig. 10b) to obtain a drag coefficien( by integratiofl. The value obtained was 1- 13, comparedwith 1.12
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