A method for estimating the effect of turbulent velocity fluctuations in the boundary layer on diffuser total-pressure-loss measurements / Jerome Persh and Bruce M. Bailey.
A method is presented for estimating the effect of turbulent velocity fluctuations on diffuser total-pressure-loss measurements. This method stipulates continuity of flow and is based on the assumption that the diffuser dimensions, inlet conditions, and the approximate distance from the wall, if fin...
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| Format: | Government Document Book |
| Language: | English |
| Published: |
Washington, D.C. :
National Advisory Committee for Aeronautics,
1954.
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| Series: | Technical note (United States. National Advisory Committee for Aeronautics) ;
3124. |
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| Summary: | A method is presented for estimating the effect of turbulent velocity fluctuations on diffuser total-pressure-loss measurements. This method stipulates continuity of flow and is based on the assumption that the diffuser dimensions, inlet conditions, and the approximate distance from the wall, if finite, to the point of zero velocity are known, that the flow is symmetrical, and that the velocity outside the boundary layer at the downstream measuring stations is not measurably influenced by the turbulent velocity fluctuations. Only the case of the conical diffuser with incompressible flow is considered. When the longitudinakl velocity fluctuations are large, as evidenced by discrepancies between the inlet and exit weight flows, the method compensates for the discrepancies by adjusting the boundary-layer profile. Total-pressure-loss coefficients by adjusting the boundary-layer profile. Total-pressure-loss coefficients estimated by the proposed method produce substantially high (more pessimistic) values than those obtained from uncorrected impact-prssure-tube surveys. Application of this method to experimental data for cases of negligible weight-flow discrepancies shows that the calculated total-pressure-loss coefficient is in agreement with the experimental value. |
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| Item Description: | "January 1954." NACA TN Number 3124. |
| Physical Description: | 16 pages : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references. |