Flowfield and acoustic properties of a Mach number 0.9 jet at a low Reynolds number

1979 ◽  
Author(s):  
J. STROMBERG ◽  
T. TROUTT
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Low Reynolds Number ◽  
Acoustic Properties ◽  
Low Reynolds

scholarly journals Simulation of Gas Flow Over a Micro Cylinder

2009 ◽  
Author(s):  
Yuan Hu ◽  
Quanhua Sun ◽  
Jing Fan
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Drag Coefficient ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Low Reynolds Number ◽  
Pressure Drag ◽  
Low Reynolds ◽  
Rarefied Gas Effect ◽  
Gas Effect

Gas flow over a micro cylinder is simulated using both a compressible Navier-Stokes solver and a hybrid continuum/particle approach. The micro cylinder flow has low Reynolds number because of the small length scale and the low speed, which also indicates that the rarefied gas effect exists in the flow. A cylinder having a diameter of 20 microns is simulated under several flow conditions where the Reynolds number ranges from 2 to 50 and the Mach number varies from 0.1 to 0.8. It is found that the low Reynolds number flow can be compressible even when the Mach number is less than 0.3, and the drag coefficient of the cylinder increases when the Reynolds number decreases. The compressible effect will increase the pressure drag coefficient although the friction coefficient remains nearly unchanged. The rarefied gas effect will reduce both the friction and pressure drag coefficients, and the vortex in the flow may be shrunk or even disappear.

scholarly journals The numerical simulation of compressible jet at low Reynolds number using OpenFOAM

2019 ◽  
Vol 128 ◽  
pp. 10008 ◽  
Author(s):  
Andrey Epikhin ◽  
Matvey Kraposhin ◽  
Kirill Vatutin
Keyword(s):  
Reynolds Number ◽  
Software Package ◽  
Low Reynolds Number ◽  
Acoustic Properties ◽  
Dynamic Parameters ◽  
Acoustic Perturbation ◽  
Flow Parameters ◽  
Gas Dynamic ◽  
Low Reynolds ◽  
Compressible Jet

The paper presents an analysis of various approaches for calculation gas-dynamic parameters and acoustic perturbations generated by a compressible jet at low Reynolds number (M = 0.9, Re = 3600). The jet flow parameters at selected conditions are well studied and can be used for validation of the numerical methods and schemes. The OpenFOAM software package with various approaches (solvers) such as pimpleCentralFoam, dbnsTurbFoam and new QGDFoam solver based on QGD-algorithms are considered. The results of time-averaged flow parameters and acoustic properties are compared with the experimental data. To determine the acoustic perturbation the Ffowcs Williams and Hawkings analogy implemented in our OpenFOAM library (libAcoustic) has been used.

Effects of Mach Number and Specific Heat Ratio on Low-Reynolds-Number Airfoil Flows

AIAA Journal ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 1640-1654 ◽  
Author(s):  
Masayuki Anyoji ◽  
Daiju Numata ◽  
Hiroki Nagai ◽  
Keisuke Asai
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Specific Heat ◽  
Low Reynolds Number ◽  
Specific Heat Ratio ◽  
Low Reynolds ◽  
Low Reynolds Number Airfoil

Effect of mach number on high-subsonic and low-Reynolds-number flows around airfoils

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040112
Author(s):  
Jian-Hua Xu ◽  
Wen-Ping Song ◽  
Zhong-Hua Han ◽  
Zi-Hao Zhao
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Reverse Flow ◽  
Separation Bubble ◽  
Low Reynolds Number ◽  
Lift Coefficient ◽  
Aerodynamic Performance ◽  
Attack Angle ◽  
Low Reynolds ◽  
Flow Vortex

High-subsonic and low-Reynolds-number flow is a special aerodynamic problem associated with near space propellers and Mars aircrafts. The flow around airfoils and the corresponding aerodynamic performance are different from the incompressible flow at low-Reynolds-number, due to complex shock wave-laminar separation bubble interaction. The objective of this paper is to figure out the effect of Mach number on aerodynamic performance and special flow structure of airfoil. An in-house Reynolds-averaged Navier–Stokes solver coupled with [Formula: see text] transition model is employed to simulate the flows around the E387 airfoil. The results show that the lift slope is larger than [Formula: see text] in the linear region. No stall occurs even at an attack angle of [Formula: see text]. With increase of Mach number, lift coefficient decreases when attack angle is below [Formula: see text]. However, once the angle of attack exceeds [Formula: see text], higher Mach number corresponds to higher lift coefficient. In addition, the strength and number of shock waves are very sensitive to Mach number. With increase of Mach number, the region of reverse flow vortex near transition location becomes smaller and finally disappears, while a new reverse flow vortex appears near the trailing edge and becomes larger.

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