Shock reflection transition in three-dimensional steady flow about interfering bodies

AIAA Journal ◽  
1983 ◽  
Vol 21 (5) ◽  
pp. 707-713 ◽  
Author(s):  
F. Marconi
Keyword(s):  
Steady Flow ◽  
Three Dimensional ◽  
Shock Reflection ◽  
Reflection Transition

500 An in vitro steady flow model of mitral regurgitation by three-dimensional Doppler

1999 ◽  
Vol 1 ◽  
pp. S86-S86
Author(s):  
R DESIMONE ◽  
G GLOMBITZA ◽  
C VAHL ◽  
H MEINZER ◽  
S HAGL
Keyword(s):  
Mitral Regurgitation ◽  
Steady Flow ◽  
Flow Model ◽  
Three Dimensional

The Effect of the Steady Flow Potential on the Motions of a Moving Ship in Waves

2000 ◽  
Vol 44 (01) ◽  
pp. 14-32
Author(s):  
Ming-Chung Fang
Keyword(s):  
Steady Flow ◽  
Present Method ◽  
Three Dimensional ◽  
Source Distribution ◽  
Series Expansions ◽  
Ship Motions ◽  
Double Integral ◽  
Flow Potential ◽  
Principal Value ◽  
Good Agreement

A three-dimensional method to analyze the motions of a ship running in waves is presented, including the effects of the steady-flow potential. Basically, the general formulations are based on the source distribution technique by which the ship hull surface is regarded as the assembly of many panels. The present study includes three algorithms for treating the corresponding Green function:the Hess & Smith algorithm for the part of simple source I/r,the complex plane contour integral of the Shen & Farell algorithm for the double integral of steady flow, andthe series expansions of the Telste & Noblesse algorithm for the Cauchy principal value integral of unsteady flow. The study reveals that the effect of steady flow on ship motions is generally small, but it still cannot be neglected in some cases, especially for the ship running in oblique waves. The effect also depends on the fore-aft configuration of the ship. The results predicted by the present method are found to be in fairly good agreement with existing experiments and other theories.

scholarly journals Stereoscopic PIV of Steady Flow Through a Bileaflet Mechanical Heart Valve

2008 ◽  
Author(s):  
C. Hutchison ◽  
P. E. Sullivan ◽  
C. R. Ethier
Keyword(s):  
Steady Flow ◽  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Shear Stresses ◽  
Stereoscopic Piv ◽  
Bileaflet Mechanical Heart Valve ◽  
Component Particle

Each year over 180,000 mechanical heart valves are implanted worldwide, with the bileaflet mechanical heart valve (BiMHV) accounting for approximately 85% of all valve replacements [1,2]. Although much improved from previous valve designs, aortic BiMHV design is far from ideal, and serious complications such as thromboembolism and hemolysis often result. Hemolysis and platelet activation are thought to be caused by turbulent Reynolds shear stresses in the flow [1]. Numerous previous studies have examined aortic BiMHV flow using LDA and two component Particle Image Velocimetry (PIV), and have shown the flow to be complex and three-dimensional [3,4]. Stereoscopic PIV (SPIV) can obtain all three velocity components on a flow plane, and hence has the potential to provide better understanding of three dimensional flow characteristics. The objective of the current study was to use SPIV to measure steady flow, including turbulence properties, downstream of a BiMHV in a modeled aorta. The resulting dataset will be useful for CFD model validation, and the intent is to make it publicly available.

REVIEW—Progress in Numerical Turbomachinery Analysis

1976 ◽  
Vol 98 (4) ◽  
pp. 592-606 ◽  
Author(s):  
David Japikse
Keyword(s):  
Numerical Analysis ◽  
Steady Flow ◽  
Transonic Flow ◽  
Three Dimensional ◽  
Flow Fields ◽  
Design Methods ◽  
Two Dimensional ◽  
Wide Spread ◽  
The Past ◽  
Turbomachinery Design

Progress achieved in numerical analysis during the past decade now permits the turbo-machinery designer to carry out a wide variety of inviscid, steady flow, two-dimensional calculations for compressible sybsonic and transonic flow fields, including some strongly diffusing flows. Three-dimensional (including viscosity) calculations are under development and should find wide spread use as analysis tools during the next decade. This review offers an introduction to recent advances in numerical turbomachinery design methods guided by the author’s design usage of several of the techniques reported.

Steady flow in a helically symmetric pipe

1998 ◽  
Vol 370 ◽  
pp. 297-320 ◽  
Author(s):  
L. ZABIELSKI ◽  
A. J. MESTEL
Keyword(s):  
Pressure Gradient ◽  
Steady Flow ◽  
Three Dimensional ◽  
Arterial System ◽  
Fully Developed Flow ◽  
Irrotational Flow ◽  
Dean Flow ◽  
Steady Pressure ◽  
Helical Pipe ◽  
Curvature And Torsion

Fully developed flow in an infinite helically coiled pipe is studied, motivated by physiological applications. Most of the bends in the mammalian arterial system curve in a genuinely three-dimensional way, so that the arterial centreline has not only curvature but torsion and can be modelled by a helix. Flow in a helically symmetric pipe generalizes related problems in axisymmetry (Dean flow) and two-dimensionality, but the geometry ensures that even irrotational flow has a cross-pipe component. Fully developed helical flows driven by a steady pressure gradient are studied analytically and numerically. Varying the radius and pitch of the helical pipe, the effects of curvature and torsion on the flow are investigated.

scholarly journals Effects of Stator Pressure Field on Upstream Rotor Performance

1999 ◽  
Author(s):  
M. B. Graf ◽  
E. M. Greitzer ◽  
F. E. Marble ◽  
O. P. Sharma
Keyword(s):  
Steady Flow ◽  
Pressure Field ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Flow Models ◽  
High Pressure Compressor ◽  
Rotor Stator Interaction ◽  
Rotor Loss

Effects of stator pressure field on upstream rotor performance in a high pressure compressor stage have been assessed using three-dimensional steady and time-accurate Reynolds-averaged Navier-Stokes computations. Emphasis was placed on: (1) determining the dominant features of the flow arising from interaction of the rotor with the stator pressure field, and (2) quantifying the overall effects on time averaged loss, blockage, and pressure rise. The time averaged results showed a 20 to 40% increase in overall rotor loss and a 10 to 50% decrease in tip clearance loss compared to an isolated rotor. The differences were dependent on the operating point and increased as the stage pressure rise, and amplitude of the unsteady back pressure variations, was increased. Motions of the tip leakage vortex on the order of the blade pitch were observed at the rotor exit in all the unsteady flow simulations; these were associated with enhanced mixing in the region. The period of the motion scaled with rotor flow-through time rather than stator passing. Three steady flow approximations for the rotor-stator interaction were assessed with reference to the unsteady computations: an axisymmetric representation of the stator pressure field, an inter-blade row averaging plane method, and a technique incorporating deterministic stresses and bodyforces associated with stator flow field. Differences between steady and unsteady predictions of overall rotor loss, tip region loss, and endwall blockage ranged from 5 to 50% of the time average, but the steady flow models gave overall rotor pressure rise and flow capacity within 5% of the time averaged values.

scholarly journals Deterministic Stress Modeling of Hot Gas Segregation in a Turbine

1999 ◽  
Author(s):  
Judy Busby ◽  
Doug Sondak ◽  
Brent Staubach ◽  
Roger Davis
Keyword(s):  
Unsteady Flow ◽  
Steady Flow ◽  
Three Dimensional ◽  
Design Tool ◽  
Source Terms ◽  
Flow Equations ◽  
Flow Solution ◽  
Viscous Solution ◽  
Hot Streak ◽  
Gas Segregation

Simulation of unsteady viscous turbomachinery flowfields is presently impractical as a design tool due to the long run times required. Designers rely predominantly on steady-state simulations, but these simulations do not account for some of the important unsteady flow physics. Unsteady flow effects can be modeled as source terms in the steady flow equations. These source terms, referred to as Lumped Deterministic Stresses (LDS), can be used to drive steady flow solution procedures to reproduce the time-average of an unsteady flow solution. The goal of this work is to investigate the feasibility of using inviscid lumped deterministic stresses to model unsteady combustion hot streak migretion effects on the turbine blade tip and outer air seal heat loads. The LDS model is obtained from an unsteady inviscid calculation. The inviscid LDS model is then used with a steady viscous computation to simulate the time-averaged viscous solution. The feasibility of the inviscid LDS model is demonstrated on a single stage, three-dimensional, vane-blade turbine with a hot streak entering the vane passage at mid-pitch and mid-span. The steady viscous solution with the LDS model is compared to the time-averaged viscous, steady viscous and time-averaged inviscid computations. The LDS model reproduces the time-averaged viscous temperature distribution on the outer air seal to within 2.3%, while the steady viscous has an error of 8.4%, and the time-averaged inviscid calculation has an error of 17.2%. The solution using the LDS model is obtained at a cost in CPU time that is 26% of that required for a time-averaged viscous computation.

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