Multi-dimensional subsonic flows around an obstacle

1991 ◽  
pp. 59-76
Keyword(s):  
Subsonic Flows

scholarly journals Eliminating flutter for clamped von Karman plates immersed in subsonic flows

2014 ◽  
Vol 13 (5) ◽  
pp. 1935-1969 ◽  
Author(s):  
Irena Lasiecka ◽  
◽  
Justin Webster ◽  
Keyword(s):  
Subsonic Flows ◽  
Von Karman ◽  
Von Kármán

A Mach-uniform preconditioner for incompressible and subsonic flows

2013 ◽  
Vol 74 (2) ◽  
pp. 100-112 ◽  
Author(s):  
Onur Bas ◽  
Ismail H. Tuncer ◽  
Unver Kaynak
Keyword(s):  
Subsonic Flows

A modified tangent-gas approximation for two-dimensional steady flow

1958 ◽  
Vol 4 (6) ◽  
pp. 600-606 ◽  
Author(s):  
G. Power ◽  
P. Smith
Keyword(s):  
Least Squares ◽  
Steady Flow ◽  
Variational Approach ◽  
Least Squares Method ◽  
Two Dimensional ◽  
Subsonic Flows ◽  
Von Karman ◽  
Straight Line ◽  
Volume Relationship ◽  
Pressure Volume Relationship

A set of two-dimensional subsonic flows past certain cylinders is obtained using hodograph methods, in which the true pressure-volume relationship is replaced by various straight-line approximations. It is found that the approximation obtained by a least-squares method possibly gives best results. Comparison is made with values obtained by using the von Kármán-Tsien approximation and also with results obtained by the variational approach of Lush & Cherry (1956).

Compressibility in suddenly expanded subsonic flows

2021 ◽  
Vol 33 (10) ◽  
pp. 105106
Author(s):  
Konstantinos Karantonis ◽  
Ioannis W. Kokkinakis ◽  
Ben Thornber ◽  
Dimitris Drikakis
Keyword(s):  
Subsonic Flows

scholarly journals Thrust Enhancement Through Bubble Injection Into an Expanding-Contracting Nozzle With a Throat

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Sowmitra Singh ◽  
Tiffany Fourmeau ◽  
Jin-Keun Choi ◽  
Georges L. Chahine
Keyword(s):  
Volume Fraction ◽  
Bubbly Flow ◽  
Design Tool ◽  
Nozzle Geometry ◽  
Mixture Flow ◽  
Subsonic Flows ◽  
Choked Flow ◽  
Optimum Geometry ◽  
Gas Volume Fraction ◽  
Gas Volume

This paper addresses the concept of thrust augmentation through bubble injection into an expanding-contracting nozzle with a throat. The presence of a throat in an expanding-contracting nozzle can result in flow transition from the subsonic regime to the supersonic regime (choked conditions) for a bubbly mixture flow, which may result in a substantial increase in jet thrust. This increase would primarily arise from the fact that the injected gas bubbles expand drastically in the supersonic region of the flow. In the current work, an analytical 1D model is developed to capture choked bubbly flow in an expanding-contracting nozzle with a throat. The study provides analytical and numerical support to analytical observations and serves as a design tool for nozzle geometries that can achieve efficient choked bubbly flows through nozzles. Starting from the 1D mixture continuity and momentum equations, along with an equation of state for the bubbly mixture, expressions for mixture velocity and gas volume fraction were derived. Starting with a fixed geometry and an imposed upstream pressure for a choked flow in the nozzle, the derived expressions were iteratively solved to obtain the exit pressures and velocities for different injected gas volume fractions. The variation of thrust enhancement with the injected gas volume fraction was also studied. Additionally, the geometric parameters were varied (area of the exit, area of the throat) to understand the influence of the nozzle geometry on the thrust enhancement and on the flow conditions at the inlet. This parametric study provides a performance map that can be used to design a bubble augmented waterjet propulsor, which can achieve and exploit supersonic flow. It was found that the optimum geometry for choked flows, unlike the optimum geometry under purely subsonic flows, had a dependence on the injected gas volume fraction. Furthermore, for the same injected gas volume fraction the optimum geometry for choked flows resulted in greater thrust enhancement compared to the optimum geometry for purely subsonic flows.

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