Steady Flows in an Oscillating Spheroidal Cavity with Elastic Wall

We develop a new mathematical model for rotational sedimentation of particles for steady flows of a viscoplastic granular fluid in a concentric-cylinder Couette geometry when rotation of the Couette cell inner cylinder is prescribed. We treat the suspension as a micro-polar fluid. The model is validated by comparison with known data of measurement. Within the proposed theory, we prove that sedimentation occurs due to particles’ rotation and rotational diffusion.

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A method for predicting Mach stem height in steady flows

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

10.1177/09544100211001518 ◽

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.

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Comparison principles for free-surface flows with gravity

Journal of Fluid Mechanics ◽

10.1017/s0022112091000770 ◽

1991 ◽

Vol 230 ◽

pp. 231-243 ◽

Cited By ~ 3

Author(s):

Walter Craig ◽

Peter Sternberg

Keyword(s):

Solitary Waves ◽

Finite Depth ◽

Free Surface Flows ◽

Immiscible Fluids ◽

Steady Flows ◽

Two Dimensional ◽

Surface Flows ◽

Ship Hulls ◽

Geometrical Information ◽

Supercritical Flows

This article considers certain two-dimensional, irrotational, steady flows in fluid regions of finite depth and infinite horizontal extent. Geometrical information about these flows and their singularities is obtained, using a variant of a classical comparison principle. The results are applied to three types of problems: (i) supercritical solitary waves carrying planing surfaces or surfboards, (ii) supercritical flows past ship hulls and (iii) supercritical interfacial solitary waves in systems consisting of two immiscible fluids.

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Some geometric acoustic problems of one-dimensional unsteady and two-dimensional steady flows

Fluid Dynamics ◽

10.1007/bf01387060 ◽

1967 ◽

Vol 2 (5) ◽

pp. 68-70

Author(s):

A. N. Kraiko

Keyword(s):

Steady Flows ◽

Two Dimensional ◽

One Dimensional

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Kinematic and Dynamic Parameters of a Liquid-Solid Pipe Flow Using DPIV∕Accelerometry

Journal of Fluids Engineering ◽

10.1115/1.2786537 ◽

2007 ◽

Vol 129 (11) ◽

pp. 1415-1421 ◽

Cited By ~ 5

Author(s):

Joseph Borowsky ◽

Timothy Wei

Keyword(s):

Pipe Flow ◽

Solid Phase ◽

Fluid Phase ◽

Central Moment ◽

Steady Flows ◽

Dynamic Parameters ◽

Two Phase ◽

Turbulence Structures ◽

Two Phases ◽

Flat Profile

An experimental investigation of a two-phase pipe flow was undertaken to study kinematic and dynamic parameters of the fluid and solid phases. To accomplish this, a two-color digital particle image velocimetry and accelerometry (DPIV∕DPIA) methodology was used to measure velocity and acceleration fields of the fluid phase and solid phase simultaneously. The simultaneous, two-color DPIV∕DPIA measurements provided information on the changing characteristics of two-phase flow kinematic and dynamic quantities. Analysis of kinematic terms indicated that turbulence was suppressed due to the presence of the solid phase. Dynamic considerations focused on the second and third central moments of temporal acceleration for both phases. For the condition studied, the distribution across the tube of the second central moment of acceleration indicated a higher value for the solid phase than the fluid phase; both phases had increased values near the wall. The third central moment statistic of acceleration showed a variation between the two phases with the fluid phase having an oscillatory-type profile across the tube and the solid phase having a fairly flat profile. The differences in second and third central moment profiles between the two phases are attributed to the inertia of each particle type and its response to turbulence structures. Analysis of acceleration statistics provides another approach to characterize flow fields and gives some insight into the flow structures, even for steady flows.

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