Journal ArticleDOI
Shock transformation and hysteresis in underexpanded confined jets
R. Arun Kumar,G. Rajesh +1 more
TLDR
In this paper, the authors investigated the shock transformation in an underexpanded jet in a confined duct when the jet total pressure is increased, and they found that the Mach reflection in the fully undereexpanded jet transforms to a regular reflection (RR) at a certain pressure.Abstract:
This study investigates the shock transformation in an underexpanded jet in a confined duct when the jet total pressure is increased. Experimental study reveals that the Mach reflection (MR) in the fully underexpanded jet transforms to a regular reflection (RR) at a certain jet total pressure. It is observed that neither the incident shock angle nor the upstream Mach number varies during the MR–RR shock transformation. This is in contradiction to the classical MR–RR transformations in internal flow over wedges and in underexpanded open jets. This transformation is found to be a total pressure variation induced transformation, which is a new kind of shock transformation. The present study also reveals that the critical jet total pressures for MR–RR and RR–MR transformations are not the same when the primary pressure is increasing and decreasing, suggesting a hysteresis in the shock transformations.read more
Citations
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Journal ArticleDOI
Physics of vacuum generation in zero-secondary flow ejectors
R. Arun Kumar,G. Rajesh +1 more
TL;DR: In this article, the authors investigate the secondary flow characteristics and the associated vacuum generation caused with an increase in the primary pressure ramping in zero-secondary flow ejectors, and they find that with the jet expansion reaching a critical level, the fluid supply from the reverse flow is suddenly entrained back into the main jet at the maximum jet expansion point.
Journal ArticleDOI
Effects of compressible flow phenomena on aerodynamic characteristics in Hyperloop system
TL;DR: In this paper, numerical simulations were conducted at various pod speeds (v p o d = 100-350 m/s) using an unsteady, compressible solver with the Reynolds-averaged Navier-Stokes model to analyze the aerodynamic characteristics and pressure wave behavior in the Hyperloop system.
Journal ArticleDOI
Investigation of a highly underexpanded jet with real gas effects confined in a channel: flow field measurements
Benoit Fond,Cheng-Nian Xiao,Christophe T’Joen,R.A.W.M. Henkes,Peter Veenstra,Berend van Wachem,Frank Beyrau +6 more
TL;DR: In this paper, the authors investigated the fluid-to-wall interaction downstream of a highly underexpanded jet, with a pressure ratio of 120, confined in a channel.
Journal ArticleDOI
Decay of supersonic rectangular jet issuing from a nozzle with diagonal expansion ramps
Surendra Bogadi,B. T. N. Sridhar +1 more
TL;DR: In this article, the effect of expansion ramps on the decay characteristics of a controlled supersonic rectangular jet was investigated and two separate nozzle models with expansion ramps placed at the diagonal ends on major and on the minor internal surface were considered for the present study.
Journal ArticleDOI
Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards
TL;DR: Geometric contributions to the mechanisms controlling eruption jet dynamics with implications for the generation of asymmetrical distributions of proximal hazards around volcanic vents are constrain.
References
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Book
Shock wave reflection phenomena
TL;DR: In this article, the authors describe shock wave reflection phenomena from a phenomenological point of view and present criteria for their formation and termination, and their governing equations are solved analytically and graphically and compared with experimental results.
Journal ArticleDOI
Ejectors: applications in refrigeration technology
K. Chunnanond,Satha Aphornratana +1 more
TL;DR: A literature review on ejectors and their applications in refrigeration can be found in this article, where a number of studies are grouped and discussed in several topics, i.e. background and theory of ejector and jet refrigeration cycle, performance characteristics, working fluid and improvement of jet refrigerator.
On the structure of jets from highly underexpanded nozzles into still air : final report
TL;DR: In this article, the position of the first normal shock in the jet behind a highly underexpanded nozzle is calculated using axial pressure distribution on the centerline of the flow behind the orifice, calculated by the method of characteristics, and the shock is then assumed to exist at that point where atmospheric pressure would be attained behind the shock.
Journal ArticleDOI
Transition to Mach reflexion of shock waves in steady and pseudosteady flow with and without relaxation
TL;DR: In this paper, the authors measured the transition conditions in pseudosteady and steady flow in the free-piston shock tube and shock tunnel with dissociating nitrogen and carbon dioxide, ionizing argon and frozen argon.
Journal ArticleDOI
On the Structure of Jets from Highly Underexpanded Nozzles Into Still Air
Thomas C. Adamson,J. A. Nicholls +1 more
TL;DR: In this article, the position of the first normal shock in the jet behind a highly underexpanded nozzle is calculated using axial pressure distribution on the centerline of the flow behind the orifice, calculated by the method of characteristics, and the shock is then assumed to exist at that point where atmospheric pressure would be attained behind the shock.