Two-dimensional and three-dimensional mixing flow fields in supersonic flow induced by injected secondary flows through traverse slot andcircular nozzle

1993 ◽  
Author(s):  
SHIGERU ASO ◽  
SATOSHI OKUYAMA ◽  
YASUNORI ANDO ◽  
TOSHIRO FUJIMORI
Keyword(s):  
Supersonic Flow ◽  
Three Dimensional ◽  
Flow Fields ◽  
Secondary Flows ◽  
Two Dimensional

The Influence of Blade Wakes on the Performance of Interturbine Diffusers

1996 ◽  
Vol 118 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. G. Dominy ◽  
D. A. Kirkham
Keyword(s):  
Performance Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean ◽  
Lp Turbine

Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

The Effect of a Wall Boundary Layer on Local Mass Transfer From a Cylinder in Crossflow

1984 ◽  
Vol 106 (2) ◽  
pp. 260-267 ◽  
Author(s):  
R. J. Goldstein ◽  
J. Karni
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Tunnel Wall ◽  
Wall Boundary Layer ◽  
Naphthalene Sublimation Technique ◽  
Displacement Thickness ◽  
Two Dimensional Flow

A naphthalene sublimation technique is used to determine the circumferential and longitudinal variations of mass transfer from a smooth circular cylinder in a crossflow of air. The effect of the three-dimensional secondary flows near the wall-attached ends of a cylinder is discussed. For a cylinder Reynolds number of 19000, local enhancement of the mass transfer over values in the center of the tunnel are observed up to a distance of 3.5 cylinder diameters from the tunnel wall. In a narrow span extending from the tunnel wall to about 0.066 cylinder diameters above it (about 0.75 of the mainstream boundary layer displacement thickness), increases of 90 to 700 percent over the two-dimensional flow mass transfer are measured on the front portion of the cylinder. Farther from the wall, local increases of up to 38 percent over the two-dimensional values are measured. In this region, increases of mass transfer in the rear portion of the cylinder, downstream of separation, are, in general, larger and cover a greater span than the increases in the front portion of the cylinder.

Reconstruction of three-dimensional flow fields from two-dimensional data

2020 ◽  
Vol 407 ◽  
pp. 109239
Author(s):  
José Miguel Pérez ◽  
Soledad Le Clainche ◽  
José Manuel Vega
Keyword(s):  
Three Dimensional ◽  
Flow Fields ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Dimensional Flow

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.

Simultaneous Optimization of Rotor Blade and Wind-Lens for Aerodynamic Design of Wind-Lens Turbine

2014 ◽  
Author(s):  
Nobuhito Oka ◽  
Masato Furukawa ◽  
Kazutoyo Yamada ◽  
Kenta Kawamitsu ◽  
Kota Kido ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Rotor Blade ◽  
Design Method ◽  
Three Dimensional ◽  
Flow Fields ◽  
Turbine Rotor ◽  
Simultaneous Optimization ◽  
Two Dimensional ◽  
Aerodynamic Design ◽  
Blade Element

An optimum aerodynamic design method for the new type of wind turbine called “wind-lens turbine” has been developed. The wind-lens turbine has a diffuser with brim called “wind-lens”, by which the wind concentration on the turbine rotor and the significant enhancement of the turbine output can be achieved. In order to design efficient wind-lens turbines, an aerodynamic design method for the simultaneous optimization of rotor blade and wind-lens has been developed. The present optimum design method is based on a genetic algorithm (GA) and a quasi-three-dimensional design of turbine rotor. In the GA procedure, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is used as evaluation and selection model. The Real-coded Ensemble Crossover (REX) is used as crossover model. The quasi-three-dimensional design consists of two parts: meridional viscous flow calculation and two-dimensional blade element design. In the meridional viscous flow calculation, an axisymmetric viscous flow is numerically analyzed on a meridional plane to determine the wind flow rate through the wind-lens and the spanwise distribution of the rotor inlet flow. In the two-dimensional rotor blade element design, the turbine rotor blade profile is determined by a one-dimensional through flow modeling for the wind-lens turbine and a two-dimensional blade element theory based on the momentum theorem of the ducted turbine. Total performances and three-dimensional flow fields of the optimized wind-lens turbines have been investigated by Reynolds averaged Navier-Stokes (RANS) simulations, in order to verify the present design method. The RANS simulations and the flow visualization have been applied to conventional and optimum design cases of the wind-lens turbine, in order to elucidate the relation between their aerodynamic performances and the flow fields around them. The numerical results show that separation vortices behind the wind-lens brim play a major role in the wind concentration and the diffuser performance of the wind-lens. As a result, it is found that the aerodynamic performance of wind-lens turbine is significantly affected by the interrelationship between the internal and external flow fields around the wind-lens.

Global stability of multiple solutions in plane sudden-expansion flow

2012 ◽  
Vol 702 ◽  
pp. 378-402 ◽  
Author(s):  
Daniel Lanzerstorfer ◽  
Hendrik C. Kuhlmann
Keyword(s):  
Secondary Flow ◽  
Mirror Symmetry ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Expansion Ratio ◽  
Secondary Flows ◽  
Sudden Expansion ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Large Expansion

AbstractThe two-dimensional, incompressible flow in a plane sudden expansion is investigated numerically for a systematic variation of the geometry, covering expansion ratios (steps-to-outlet heights) from $0. 25$ to $0. 95$. By means of a three-dimensional linear stability analysis global temporal modes are scrutinized. In a symmetric expansion the primary bifurcation is stationary and two-dimensional, breaking the mirror symmetry with respect to the mid-plane. The secondary asymmetric flow experiences a secondary instability to different three-dimensional modes, depending on the expansion ratio. For a moderately asymmetric expansion only one of the two secondary flows (the connected branch) is realized at low Reynolds numbers. Since the perturbed secondary flow does not deviate much from the symmetric secondary flow, both secondary stability boundaries are very close to each other. For very small and very large expansion ratios an asymptotic behaviour is found for suitably scaled critical Reynolds numbers and wavenumbers. Representative instabilities are analysed in detail using an a posteriori energy transfer analysis to reveal the physical nature of the instabilities. Depending on the geometry, pure centrifugal and elliptical amplification processes are identified. We also find that the basic flow can become unstable due to the effects of flow deceleration, streamline convergence and high shear stresses, respectively.

The Influence of Blade Wakes on the Performance of Inter-Turbine Diffusers

1994 ◽  
Author(s):  
Robert G. Dominy ◽  
David A. Kirkham
Keyword(s):  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Performance Modelling ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean

Inter-turbine diffusers provide continuity between H.P. and LP turbines whilst diffusing the flow upstream of the L.P. turbine. Increasing of the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages leading to increased efficiency. The flows associated with these inter-turbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that full three-dimensional, viscous analysis methods are essential for correct performance modelling.

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