Scaling law for shock-cell length and its correlation with shock-associated noise of circular and elliptic supersonic free jets

2021 ◽  
Vol 33 (9) ◽  
pp. 096103
Author(s):  
Arun Kumar Perumal ◽  
Ethirajan Rathakrishnan
Keyword(s):  
Scaling Law ◽  
Cell Length ◽  
Shock Cell ◽  
Free Jets

scholarly journals Scaling law for supersonic core length in circular and elliptic free jets

2021 ◽  
Vol 33 (5) ◽  
pp. 051707
Author(s):  
Arun Kumar Perumal ◽  
Ethirajan Rathakrishnan
Keyword(s):  
Scaling Law ◽  
Free Jets ◽  
Core Length ◽  
Supersonic Core Length

Noisefield of Underexpanded Notched Circular-Slot Jets

2002 ◽  
Vol 33 (6) ◽  
pp. 9-23
Author(s):  
S.B. Verma ◽  
E. Rathakrishnan
Keyword(s):  
Acoustic Emission ◽  
Aspect Ratio ◽  
Cell Length ◽  
Emission Characteristics ◽  
Far Field ◽  
Shock Cell ◽  
Acoustic Spectrum ◽  
Compression Waves ◽  
Noise Field ◽  
Notch Geometry

The effect of notches on the flow and noise field of jets from circular-slots is experimentally investigated. Three types of slot geometries, namely, semicircular, triangular and square are studied. The results demonstrate that the presence of the notch introduces a slight aspect-ratio in the initial circular-slot geometry so that the notched jet exhibits characteristics, similar to jets exiting from non-circular geometries. At underexpanded condition, additional expansion and compression waves are observed to emanate from the region of notches that modifies the jet development and results in a reduction in the average shock-cell length, which is accompanied by a reduction in far-field shock associated noise. The acoustic spectrum of the radiated shock noise indicates that notch geometry variation strongly alters the acoustic emission characteristics of these jets both in the screech component and broadband shock associated noise.

An experimental and numerical investigation of under-expanded turbulent jets

2004 ◽  
Vol 108 (1081) ◽  
pp. 145-152 ◽  
Author(s):  
A. J. Saddington ◽  
N. J. Lawson ◽  
K. Knowles
Keyword(s):  
Turbulence Model ◽  
Nozzle Exit ◽  
Experimental Studies ◽  
Independent Solution ◽  
Turbulent Jets ◽  
Cell Length ◽  
Cfd Model ◽  
Shock Cell ◽  
Probe Measurements ◽  
Good Agreement

AbstractThe work described here concentrates on under-expanded, axisym-metric turbulent jets issuing into quiescent conditions. Under-expanded turbulent jets are applicable to most aircraft propulsion applications that use convergent nozzles. Experimental studies used laser doppler velocimetry (LDV) and pitot probe measurements along the jet centreline. These measurements were made for two nozzle pressure ratios (2·5 and 4·0) and at various streamwise positions up to 10 nozzle diameters downstream of the nozzle exit plane. A computational fluid dynamics (CFD) model was developed using the Fluent code and utilised the RNG K-ε two-equation turbulence model. A mesh resolution of approximately one hundredth of nozzle exit diameter was found to be sufficient to establish a mesh independent solution.Comparison of the jet centreline axial velocity (LDV data) and pressure ratio (pitot probe data) showed good agreement with the CFD model. The correct number of shock cells had been predicted and the shock strength agreed well between the experiments and numerical model. The CFD model was, however, found to over-predict the shock cell length resulting in a longer supersonic core. There was some evidence, based on analysis of the LDV measurements that indicates the presence of swirl and jet unsteadiness, which could contribute to a shortening of the shock cell length. These effects were not modelled in the CFD. Correlation between the LDV and pitot probe measurements was generally good, however, there was some evidence that probe interference may have caused the premature decay of the jet. Overall, this work has indicated the good agreement between a CFD simulation using the RNG k-ε turbulence model and experimental data when applied to the prediction of the flowfield generated by under-expanded turbulent jets. The suitability of the LDV technique to jet flows with velocities up to 500ms-1has also been demonstrated.

An experimental and numerical investigation of under-expanded turbulent jets

2004 ◽  
Vol 108 (1081) ◽  
pp. 145-152 ◽  
Author(s):  
A. J. Saddington ◽  
N. J. Lawson ◽  
K. Knowles
Keyword(s):  
Turbulence Model ◽  
Nozzle Exit ◽  
Experimental Studies ◽  
Independent Solution ◽  
Turbulent Jets ◽  
Cell Length ◽  
Cfd Model ◽  
Shock Cell ◽  
Probe Measurements ◽  
Good Agreement

AbstractThe work described here concentrates on under-expanded, axisym-metric turbulent jets issuing into quiescent conditions. Under-expanded turbulent jets are applicable to most aircraft propulsion applications that use convergent nozzles. Experimental studies used laser doppler velocimetry (LDV) and pitot probe measurements along the jet centreline. These measurements were made for two nozzle pressure ratios (2·5 and 4·0) and at various streamwise positions up to 10 nozzle diameters downstream of the nozzle exit plane. A computational fluid dynamics (CFD) model was developed using the Fluent code and utilised the RNG K-ε two-equation turbulence model. A mesh resolution of approximately one hundredth of nozzle exit diameter was found to be sufficient to establish a mesh independent solution.Comparison of the jet centreline axial velocity (LDV data) and pressure ratio (pitot probe data) showed good agreement with the CFD model. The correct number of shock cells had been predicted and the shock strength agreed well between the experiments and numerical model. The CFD model was, however, found to over-predict the shock cell length resulting in a longer supersonic core. There was some evidence, based on analysis of the LDV measurements that indicates the presence of swirl and jet unsteadiness, which could contribute to a shortening of the shock cell length. These effects were not modelled in the CFD. Correlation between the LDV and pitot probe measurements was generally good, however, there was some evidence that probe interference may have caused the premature decay of the jet. Overall, this work has indicated the good agreement between a CFD simulation using the RNG k-ε turbulence model and experimental data when applied to the prediction of the flowfield generated by under-expanded turbulent jets. The suitability of the LDV technique to jet flows with velocities up to 500ms-1has also been demonstrated.

Scaling Law of Coupling Coefficient and Coil Size in Wireless Power Transfer Design via Magnetic Coupling

2017 ◽  
Vol 137 (4) ◽  
pp. 326-333
Author(s):  
Chiaki Nagai ◽  
Kenji Inukai ◽  
Masato Kobayashi ◽  
Tatsuya Tanaka ◽  
Kensho Abumi ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Scaling Law ◽  
Magnetic Coupling ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Coil Size

Energy Propagation in Heated Turbulent Free Jets

1987 ◽  
Author(s):  
L. Gbahoué ◽  
S. Lecume ◽  
J.L. Carreau ◽  
Ph. Hobbes ◽  
F. Roger
Keyword(s):  
Energy Propagation ◽  
Free Jets
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