A FLUID MODELING STUDY OF THE FLOW STRUCTURE AND PLUME IMPINGEMENT ON A THREE-DIMENSIONAL HILL IN STABLY STRATIFIED FLOW

In stably stratified flow over a three-dimensional hill, we can define a dividing streamline that separates those streamlines that pass around the hill from those that pass over the hill. The height Hs of this dividing streamline can be estimated by Sheppard's simple energy argument; fluid parcels originating far upstream of a hill at an elevation above Hs have sufficient kinetic energy to rise over the top, whereas those below Hs must pass around the sides. This prediction provides the basis for analysing an extensive range of laboratory observations and measurements of stably stratified flow over a variety of shapes and orientations of hills and with different upwind density and velocity profiles. For symmetric hills and small upwind shear, Sheppard's expression provides a good estimate for Hs. For highly asymmetric flow and/or in the presence of strong upwind shear, the expression provides a lower limit for Hs. As the hills become more nearly two-dimensional, these experiments become less well defined because steady-state conditions take progressively longer to be established. The results of new studies are presented here of the development of the unsteady flow upwind of two-dimensional hills in a finite-length towing tank. These measurements suggest that a very long tank would be required for steady-state conditions to be established upstream of long ridges with or without small gaps and cast doubt upon the validity of previous laboratory studies.

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COHERENT STRUCTURE IN THE NEAR WAKE FROM A HEATED OR UNHEATED CIRCULAR CYLINDER IMMERSED IN A STABLY STRATIFIED FLOW

Proceeding of International Heat Transfer Conference 11 ◽

10.1615/ihtc11.3220 ◽

1998 ◽

Author(s):

Kyung Chun Kim

Keyword(s):

Circular Cylinder ◽

Coherent Structure ◽

Stratified Flow ◽

Near Wake ◽

Stably Stratified Flow

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Characterization of the three dimensional turbulent flow structure of angled injection into a supersonic cross flow

10.2514/6.1996-2662 ◽

1996 ◽

Author(s):

R. Bowersox

Keyword(s):

Turbulent Flow ◽

Flow Structure ◽

Three Dimensional ◽

Cross Flow ◽

Turbulent Flow Structure

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The inlet flow structure of a conceptual open-nose supersonic drone

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020983043 ◽

2021 ◽

pp. 095441002098304

Author(s):

Eiman B Saheby ◽

Xing Shen ◽

Anthony P Hays ◽

Zhang Jun

Keyword(s):

Flow Structure ◽

Stokes Equations ◽

Fluid Dynamic ◽

Three Dimensional ◽

Computational Fluid Dynamic Simulation ◽

Navier Stokes ◽

Ansys Fluent ◽

Navier Stokes Equations ◽

Aerodynamic Efficiency ◽

Performance Effects

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

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