Large scale advanced propeller blade pressure distributions - Prediction and data

Nallasamy, M.; Yamamoto, Osamu; Warsi, Saif; Bober, L. J.

doi:10.2514/6.1989-2696

Cited by 6 publications

(2 citation statements)

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“…7 It was found that with increasing Mach number, more significant changes occurred on the suction side than on the pressure side. The evidence of a compression wave started to develop when the Mach number reached 0.7.…”

Section: Introductionmentioning

confidence: 97%

Unsteady blade pressures on a propfan - Predicted and measured compressibility effects

Nallasamy¹

1994

Journal of Aircraft

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The effect of compressibility on unsteady blade pressures is studied by solving the three-dimensional Euler equations. The operation of the eight-bladed SR7L propfan at 4.75' angle of attack was considered. Euler solutions were obtained for three Mach numbers, 0.6, 0.7 and 0.8 and the predicted blade pressure waveforms were compared with flight data. The comparisons show that in general, the effect of Mach number on pressure waveforms are correctly predicted. The change in pressure waveforms are minimal when the Mach number is increased from 0.6 to 0.7. Increasing the Mach number from 0.7 to 0.8 produces significant changes in predicted pressure levels. The predicted amplitudes, however, differ from measurements at some transducer locations. Also the predicted appearance of a shock in the highly loaded portion of the blade revolution is not indicated by the measurements. At all the three Mach numbers, the measured (installed propfan) pressure waveforms show a relative phase lag compared to the computed (prop fan alone) waveforms due to installation effects. Measured waveforms in the blade tip region show nonlinear variations which are not captured by the present numerical procedure.

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Section: Introductionmentioning

confidence: 97%

Unsteady blade pressures on a propfan - Predicted and measured compressibility effects

Nallasamy¹

1994

Journal of Aircraft

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“…These schemes include traditional approaches like finite element [71][72][73][74][75] and finite difference methods [76][77][78][79][80][81][82] as well as efficient new methodologies like vortex method [83][84][85][86][87][88][89][90][91][92][93][94][95][96] or spectral method [97][98][99][100][101][102][103][104][105][106][107] which can simulate vortical structures in separated fields particularly well.…”

Section: Introductionmentioning

confidence: 99%

Efficient Simulation and Novel Modeling by Using Generic Three-Dimensional Exact Solutions to Analyze Transport Dynamics in Turbulent Vortices

Bhattacharya¹

2009

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REPORT DOCUMENTATION PAGEThe public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for _ , «.a,., y existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense, Executive Service Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)AFOSR 875 N RANDOLPH ST ARLINGTON, VA 22203 Dr. John Schmisseur/NA SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTDistribution A -Approved for public release SUPPLEMENTARY NOTES ABSTRACTIn this project, we have formulated an alternative boundary-layer theory. This new analysis will be able to mathematically describe flow-separation unlike the classical theory. In our research, we have partially validated the developed theory and concluded that approach has considerable potential to account for flow-separation. The effective description of separated flow can potentially lead to a fast simulation-algorithm for aerodynamic computation. Our estimate predicts that this semianalytical scheme will compute the lift and drag on an aerodynamic body in less than O.lsec with less than l\% relative error. This is more than hundredfold increase over current simulation-efficiency. The enhanced efficiency will enable hitherto impossible exploration of new designs for maximization of the lift to drag ratio. In the future, this will revolutionize aviation technology by the development of bio-inspired aviation mechanism and other novel systems. Such improvements will help in energy-savings and pollution control by reducing fuel consumptions. SUBJECT TERMSAlternative boundary-layer theory, flow-separation, fast aerodynamic algorithm Flow-separation from a rigid body is an unsolved problem in theoretical fluid mechanics in spite of the maturity of this field. Classical boundary-layer theory cannot provide a complete description and quantitative estimates for such phenomenon. For example, it is not possible to determine the vortical structures in separated flows by using boundary-layer equation in the wake region [1][2][3][4][5][6][7]. Similarly, there is no easy way to predict the strength of the eddies without extensive computations [8,9]. Unfortunately, subsequent theoretical developments, like triple-deck theory [10][11][12][13] or other viscous-inviscid analysis [14-21] have not been able to overcome these deficiencies.The lack of mathematical understanding of flow-separation is a severe hindrance in aerodynamic analysis. In absence of an analytical method, the bru...

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Integration of Airfoil Stall and Compressibility Models into a Propeller Blade Element Model

Dorfling

Rokhsaz

2016

J. Aerosp. Eng.

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Large scale advanced propeller blade pressure distributions - Prediction and data

Cited by 6 publications

References 5 publications

Unsteady blade pressures on a propfan - Predicted and measured compressibility effects

Unsteady blade pressures on a propfan - Predicted and measured compressibility effects

Efficient Simulation and Novel Modeling by Using Generic Three-Dimensional Exact Solutions to Analyze Transport Dynamics in Turbulent Vortices

Integration of Airfoil Stall and Compressibility Models into a Propeller Blade Element Model

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