- Volume 16 Issue 2
The present study numerically investigates the effect of shield on the flow characteristics of Hartmann whistle. The flow characteristics of un-shielded Hartmann whistle are compared with whistles of different shield heights 15 mm, 17 mm, 20 mm, 25 mm and 30 mm. The comparison of Mach number contours and transient velocity vectors of shielded Hartmann whistles with un-shielded ones for the same conditions reveal that the presence of shield causes the exiting jet to stick to the wall of the shield without causing spill-over around the cavity inlet, thus sustaining the shock oscillation as seen in the unshielded Hartmann whistle, which has intense flow/shock oscillation and spill-over around the cavity mouth. The velocity vectors indicate jet regurgitance in shielded whistles showing inflow and outflow phases like un-shielded ones with different regurgitant phases. The sinusoidal variation of mass flow rate at the cavity inlet in un-shielded Hartmann whistle indicates jet regurgitance as the primary operating mode with large flow diversion around the cavity mouth whereas the non-sinusoidal behavior in shielded ones represent that the jet regurgitance is not the dominant operating mode. Thus, this paper sufficiently demonstrates the effect of shield in modifying the flow/shock oscillations in the vicinity of the cavity mouth.
Hartmann Whistle;Shielding Effect
- S. Narayanan, K. Srinivasan, T. Sundararajan, and K. Ramamurthi, "Acoustic characteristics of chamfered Hartmann whistles", Journal of Sound and Vibration, Vol. 330, 2011, pp. 2470-2496. https://doi.org/10.1016/j.jsv.2010.12.003
- G. Raman, and K. Srinivasan, "The powered resonance tube: from Hartmann's discovery to current active flow control applications", Progress in Aerospace Sciences, Vol. 45, 2009, pp. 97-123. https://doi.org/10.1016/j.paerosci.2009.05.001
- P. R. Spalart, and S. R. Allmaras, "A One-equation Turbulence Model for Aerodynamic Flows", American Institute of Aeronautics and Astronautics, 1992, AIAA-92-0439.
- C.K.W. Tam, Jet noise generated by large-scale coherent motion, in: H.H. Hubbard (Ed.), Aeroacoustics of Flight Vehicles, Theory and Practice, vol. 1, Acoustical Society of America, Melville, 1995, pp. 1095.
- C.K.W. Tam, H.K. Tanna, "Shock associated noise of supersonic jets from convergent-divergent nozzles", Journal of Sound and Vibration, Vol. 81, 1982, pp. 337-358. https://doi.org/10.1016/0022-460X(82)90244-9
- S.M .Chang, and S. Lee, "On the jet regurgitant mode of a resonant tube", Journal of Sound and Vibration, Vol. 246, No.4, 2001, pp. 567-581. https://doi.org/10.1006/jsvi.2000.3646
- A. Hamed, K. Das, and D. Basu, "Characterization of powered resonance tube for high frequency excitation", Proceedings of FEDSM'03 4TH ASME- JSME Joint Fluids Engineering Conference Honolulu, FEDSM 2003-45472, Hawaii, USA, 2003.
- E. Brun, and R.M.G. Boucher, "Research on the acoustic air-jet generator: a new development", Journal of the Acoustical Society of America, Vol. 29, No. 5, 1957, pp.573-583. https://doi.org/10.1121/1.1908969
- G. Raman, S. Khanafseh, A.B. Cain, and E. Kerschen, "Development of high bandwidth powered resonance tube actuators with feedback control", Journal of Sound and Vibration, Vol. 269, No. 3-5, 2004, pp. 1031-1062. https://doi.org/10.1016/S0022-460X(03)00212-8
- G. J. Sreejith, S. Narayanan, T. J. S. Jothi, and K. Srinivasan, "Studies on conical and cylindrical resonators", Applied Acoustics, Vol. 69, No. 12, 2008, pp. 1161-1175. https://doi.org/10.1016/j.apacoust.2007.11.009
- J.W. Gregory, and J.P. Sullivan, "Characterization of Hartmann tube flow with porous pressure sensitive paint", Proceedings of the 33rd AIAA Fluid Dynamics Conference and Exhibit, Orlando FL, 2003.
- J. Kastner, and M. Samimy, "Development and characterization of Hartmann tube fluidic actuators for high-speed control", American Institute of Aeronautics and Astronautics Journal, Vol. 40, No. 10, 2002, pp. 1926-1934. https://doi.org/10.2514/2.1541
- E. Brocher, C. Maresca, and M.H. Bournay, "Fluid dynamics of the resonance tube", Journal of Fluid Mechanics, Vol. 43, No. 2, 1970, pp. 369-384. https://doi.org/10.1017/S0022112070002422
- Hartmann, J. (1919) Om en ny methode til frembringelse af lydsvinginger. DanMat Fys Medd, 1:13.
- K.S. Chang, K.H. Kim, and J. Iwamoto, "A study on the Hartmann Sprenger tube flow driven by a sonic jet", International Journal of Turbo and Jet Engines, Vol. 13, 1996, pp.173-182.
- The Influence of Acoustic Field Induced by HRT on Oscillation Behavior of a Single Droplet vol.10, pp.12, 2017, https://doi.org/10.3390/en10010048
- Numerical simulation of a sonic-underexpanded jet impinging on a partially covered cylindrical Hartmann whistle 2017, https://doi.org/10.1177/0037549717741202