Consideration of Local Wind Energy

1998 ◽  
Vol 10 (5) ◽  
pp. 445-449
Author(s):  
Kouki Yamaji ◽  
◽  
Takaaki Hashimoto ◽  
Shoushi Inoue ◽  
Yutaka Konishi ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Velocity ◽  
Potential Flow ◽  
Electricity Generation ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Local Wind ◽  
Local Winds

We measured local wind velocity and direction on a hill west of Gamagori City for about 4.5 years, finding that the average annual wind velocity is 3.3m/s and wind with velocity exceeding 4m/s blows over 2500 hours a year. We concluded that useful local wind energy exists based on the electricity generation standard. Three-dimensional incompressible potential flow analysis clarified local winds.

scholarly journals Design and Testing of Swept and Leaned Outlet Guide Vanes to Reduce Stator-Strut-Splitter Aerodynamic Flow Interactions

1998 ◽  
Author(s):  
A. R. Wadia ◽  
P. N. Szucs ◽  
K. L. Gundy-Burlet
Keyword(s):  
Dimensional Analysis ◽  
Test Performance ◽  
Potential Flow ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Angle Distribution ◽  
Two Dimensional ◽  
Guide Vanes ◽  
Flow Interactions ◽  
Design And Testing

Large circumferential varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single bladerow three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV-frame system to obtain a circumferentially non-uniform stator stagger angle distribution to further reduce the upstream static pressure disturbance. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV-strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The three-dimensional coupled OGV-frame analysis included the uniformly-staggered OGVs configuration and the variably-staggered OGVs configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the three-dimensional analysis revealed significant flow problems with the variably-staggered OGVs configuration and showed less upstream flow non-uniformity with the uniformly-staggered OGVs configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow non-uniformity with the uniformly-staggered OGVs configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly- and variably-staggered OGVs configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.

Design and Testing of Swept and Leaned Outlet Guide Vanes to Reduce Stator–Strut–Splitter Aerodynamic Flow Interactions

1999 ◽  
Vol 121 (3) ◽  
pp. 416-427 ◽  
Author(s):  
A. R. Wadia ◽  
P. N. Szucs ◽  
K. L. Gundy-Burlet
Keyword(s):  
Dimensional Analysis ◽  
Potential Flow ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Angle Distribution ◽  
Two Dimensional ◽  
Guide Vanes ◽  
Flow Interactions ◽  
Design And Testing ◽  
Flow Nonuniformity

Large circumferentially varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single blade row three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV–frame system to obtain a circumferentially nonuniform stator stagger angle distribution to reduce the upstream static pressure disturbance further. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV–strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The three-dimensional coupled OGV–frame analysis included the uniformly staggered OGV configuration and the variably staggered OGV configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the three-dimensional analysis revealed significant flow problems with the variably staggered OGV configuration and showed less upstream flow nonuniformity with the uniformly staggered OGV configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow nonuniformity with the uniformly staggered OGV configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly and variably staggered OGV configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.

On Aerodynamic Stability of Membrane Structures

2005 ◽  
Vol 20 (3) ◽  
pp. 181-188 ◽  
Author(s):  
Qing-Shan Yang ◽  
Rui-Xia Liu
Keyword(s):  
Wind Velocity ◽  
Potential Flow ◽  
Dynamic Equilibrium ◽  
Three Dimensional ◽  
Flow Theory ◽  
Membrane Structures ◽  
Moment Theory ◽  
Shallow Shells ◽  
Potential Flow Theory ◽  
Critical Wind Velocity

The aerodynamic instability critical wind velocity of three-dimensional membrane structures is studied by combining the non-moment theory of thin shallow shells and the potential flow theory in fluids. The dynamic equilibrium equation of the structure is established by applying the non-moment theory of thin shells, with the assumption that the coming flow is uniform ideal potential flow. The aerodynamic interaction equations of the membrane structure in two cases, i.e., the wind is in the structural arch or sag direction, are obtained based on the aerodynamic forces being determined by applying the potential flow theory and the thin airfoils theory in which the wind-structure interaction is taken into account. Bubnov-Galerkin approximate method is applied to transform the interaction equation into a second order linear ordinary differential equation; and the instability critical wind velocity is obtained from Routh-Hurwitz stability criterion.

The Effect of Radius Change on Two-Dimensional Cascade Solutions

1985 ◽  
Author(s):  
Joseph R. Caspar ◽  
David E. Hobbs
Keyword(s):  
Potential Flow ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Rotating Frame ◽  
Steady Flows ◽  
Two Dimensional ◽  
Potential Solution ◽  
Radius Variation ◽  
Stators And Rotors ◽  
Euler Solution

The effects of varying radius along a streamsurface are included in a two dimensional blade-to-blade potential flow analysis of turbomachinery rotors and stators in order to model better three dimensional effects. On a cylindrical streamsurface, flows in rotors can be treated as steady flows in the rotating frame; the rotation can be ignored. On a streamsurface with varying radius, however, the flow, even in the rotating frame, is not potential. Thus the physical flow is related to a non-physical, potential flow for calculation purposes. Computed results for compressor stators and rotors show that the potential solution agrees well with an Euler solution, that effects of radius variation are very important for both stators and rotors, and that effects of radius contouring and of rotation can also be important.

VISCOUS POTENTIAL FLOW ANALYSIS OF STRESS-INDUCED CAVITATION IN AN APERTURE FLOW

2006 ◽  
Vol 16 (7) ◽  
pp. 763-776 ◽  
Author(s):  
T. Funada ◽  
J. Wang ◽  
Daniel D. Joseph
Keyword(s):  
Potential Flow ◽  
Flow Analysis ◽  
Viscous Potential Flow
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