Computation of Subsonic Flow Region

1973 ◽  
pp. 60-79
Author(s):  
Gorimir G. Cherny
Keyword(s):  
Subsonic Flow ◽  
Flow Region

scholarly journals Subsonic flow region on blunted cones in supersonic flow.

1987 ◽  
Vol 35 (400) ◽  
pp. 253-259 ◽  
Author(s):  
Takashi TANI ◽  
Norio ARAI ◽  
Koetsu TAKEHANA ◽  
Hideo SEKINE ◽  
Naoki HIROSE
Keyword(s):  
Supersonic Flow ◽  
Subsonic Flow ◽  
Flow Region

scholarly journals Heating and Momentum Deposition in Hot Stars

1992 ◽  
Vol 9 ◽  
pp. 649-650
Author(s):  
J.I. Castor
Keyword(s):  
Subsonic Flow ◽  
Flow Region ◽  
Hot Stars ◽  
Cool Star ◽  
Cool Stars ◽  
Spatially Extended ◽  
The One ◽  
Energy And Momentum ◽  
Outer Corona ◽  
The Magnetic Field

The one great point of similarity between the coronae of hot and cool stars is that both are spatially extended regions of more-or-less tenuous gas that is flowing outward, and at least some of which is at a temperature in excess of 106 K. Coronae defined in this way are almost universal among stars—excepting cool supergiants—but this similarity may hide significant differences in the processes that produce coronae. There are two rather different paradigms for their origin: the cool-star paradigm and the hot star paradigm.The coronae of cool stars like the sun are of such a low density that radiative cooling is inefficient; the outward flow is weak enough that there is a fairly extended subsonic flow region. The outer corona is heated by a flux of wave energy, and some of this energy is then conducted inward to heat the inner corona. The outflow is driven by the pressure of the heated gas, assisted perhaps by wave pressure. The structure of the corona is greatly affected by the topology of the magnetic field, which channels the outflow and governs the transport of energy and momentum by waves.

scholarly journals Modification of Airflow Structure Due to Wave Breaking on a Submerged Topography

2021 ◽  
Author(s):  
Petter Vollestad ◽  
Atle Jensen
Keyword(s):  
Wind Wave ◽  
Separated Flow ◽  
Flow Region ◽  
Breaking Waves ◽  
Leeward Side ◽  
Geometrical Properties ◽  
Image Velocimetry ◽  
Wind Profiles ◽  
The Waves ◽  
Sheltered Area

AbstractExperimental results from a combined wind–wave tank are presented. Wind profiles and resulting wind–wave spectra are described, and an investigation of the airflow above breaking waves is presented. Monochromatic waves created by the wave maker are directed towards a submerged topography. This causes the waves to break at a predictable location, facilitating particle-image-velocimetry measurements of the airflow above steep breaking and non-breaking waves. We analyze how the breaking state modifies the airflow structure, and in particular the extent of the sheltered area on the leeward side of the waves. Results illustrate that while the geometrical properties of the waves greatly influence the airflow structure on the leeward side of the waves, the state of breaking (i.e., whether the waves are currently in a state of active breaking) is not observed to have a clear effect on the extent of the separated flow region, or on the velocity distribution within the sheltered region.

A method for predicting Mach stem height in steady flows

2021 ◽  
pp. 095441002110015
Author(s):  
Song-Guk Choe
Keyword(s):  
Analytical Model ◽  
Slip Line ◽  
Flow Region ◽  
Rocket Engines ◽  
Steady Flows ◽  
Mach Stem ◽  
Stem Height ◽  
Mach Numbers ◽  
Relative Errors ◽  
Cfd Method

The prediction of Mach stem height can be important in the design of supersonic intake in supersonic and hypersonic flows. It is also important because of the progress in aircraft and rocket engines. An analytical method of predicting the Mach stem height is necessary in theoretical field of shock reflection and is the basis of the comparable computational fluid dynamics (CFD) method. A method for predicting the Mach stem height in steady flows is performed based on the earlier models. In this article, an analytical model for predicting the Mach stem height is improved based on two main assumptions: one is the calculation of the triple point deflection angle when the Mach stem is an oblique shock and the other is about the shape of the free part of the slip line. Under these assumptions, the relations predicting of Mach stem height in two-dimensional steady flow are derived based on the advanced averaging method of the subsonic flow region. The Mach stem heights are decided solely for the incoming flow Mach numbers and the wedge angles by the improved analytical model. As a result, the Mach stem heights by the model of this article are found to agree well with experimental results at lower Mach numbers, but there are relative errors at higher Mach numbers. The convexity of the slip line is also considered.

Thermally developing forced convection flow through porous concentric pipes annular duct

2021 ◽  
pp. 095440622110022
Author(s):  
Farhan Ahmed
Keyword(s):  
Flow Region ◽  
Axial Direction ◽  
Darcy Number ◽  
Convection Flow ◽  
Axial Distance ◽  
Cross Sectional ◽  
Developing Flow ◽  
Annular Sector ◽  
Flow Through ◽  
The Cross

This article shows the thermally developing flow through concentric pipes annular sector duct by describing the Darcy Brinkman flow field. The cross sectional convection-diffusion terms are transformed in power law discretized form by integrating over the differential volume, whereas backward difference scheme is used in the axial direction of heat flow. With the help of semi implicit method for pressure linked equations-revised ( SIMPLE-R), we get the solution of the governing problem. The graphs of velocity profiles against R and average Nusselt number against axial distance are plotted for different values of Darcy number and geometrical configuration parameters. It has been pointed out that velocity and thermal entrance length decrease, when we decrease the value of Darcy number. By decreasing the cross section of the concentric pipes annular sector duct in the transverse direction, thermally fully developed flow region develops earlier.

scholarly journals Laser-Doppler Velocimetry Measurements Inside a Backward Curved Centrifugal Fan

2001 ◽  
Vol 7 (3) ◽  
pp. 173-181
Author(s):  
Tong-Miin Liou ◽  
Meng-Yu Chen
Keyword(s):  
Flow Rate ◽  
Turbulence Intensity ◽  
Laser Doppler Velocimetry ◽  
Reverse Flow ◽  
Flow Region ◽  
Design Flow ◽  
Laser Doppler ◽  
Centrifugal Fan ◽  
Doppler Velocimetry ◽  
Flow Rates

Laser-Doppler velocimetry (LDV) measurements are presented of relative mean velocity and turbulence intensity components inside the impeller passage of a centrifugal fan with twelve backward curved blades at design, under-design, and over-design flow rates. Additional LDV measurements were also performed at the volute outlet to examine the uniformity of the outlet flow for the three selected flow rates. Complementary flow visualization results in the tongue region are further presented. It is found that the number of characteristic flow regions and the average turbulence level increase with decreasing air flow rate. For the case of under-design flow rate, there are a through-flow region on the suction side, a reverse flow region on the pressure side, and a shear layer region in between. The corresponding average turbulence intensity is as high as 9.1% of blade tip velocity.

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