scholarly journals Aerodynamic Design for Three- Dimensional Multi- lifting Surfaces at Transonic Flow

2006 ◽  
Vol 19 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Qing-zhen YANG ◽  
Zhong-yin ZHANG ◽  
Streit Thomas ◽  
Wichmann Georg ◽  
Yong ZHENG
Author(s):  
S. V. Subramanian ◽  
R. Bozzola ◽  
Louis A. Povinelli

The performance of a three dimensional computer code developed for predicting the flowfield in stationary and rotating turbomachinery blade rows is described in this study. The four stage Runge-Kutta numerical integration scheme is used for solving the governing flow equations and yields solution to the full, three dimensional, unsteady Euler equations in cylindrical coordinates. This method is fully explicit and uses the finite volume, time marching procedure. In order to demonstrate the accuracy and efficiency of the code, steady solutions were obtained for several cascade geometries under widely varying flow conditions. Computed flowfield results are presented for a fully subsonic turbine stator and a low aspect ratio, transonic compressor rotor blade under maximum flow and peak efficiency design conditions. Comparisons with Laser Anemometer measurements and other numerical predictions are also provided to illustrate that the present method predicts important flow features with good accuracy and can be used for cost effective aerodynamic design studies.


1959 ◽  
Vol 3 (01) ◽  
pp. 10-21 ◽  
Author(s):  
Charles J. Henry ◽  
John Dugundji ◽  
Holt Ashley

The large increases anticipated in speeds of vehicles towed or propelled underwater suggests a re-examination of the problem of stability of flexible lifting surfaces mounted thereon. Experimental and theoretical evidence is assembled which suggests that oscillatory aeroelastic instability (flutter) is very unlikely at the structural-to-fluid mass ratios typical of hydrodynamic operation. It is shown that static instability (divergence) is the more important practical problem but that its occurrence can be predicted with greater confidence. Flutter data obtained in high-density fluids are reviewed, and various sources of inaccuracy in their theoretical prediction are analyzed. The need is expressed for more precise means of analytically representing both dynamic-elastic systems and three-dimensional unsteady hydrodynamic loads. For a simple hydrofoil with single degrees of freedom in bending and torsion, the theoretical influence of several significant parameters on high-density flutter is calculated and discussed. Recommendations are made for refinements to existing techniques of analysis to include the presence of channel boundaries, free surfaces, cavitation or separated flow.


2020 ◽  
Vol 08 (04) ◽  
pp. 295-308
Author(s):  
Yuchen Leng ◽  
Murat Bronz ◽  
Thierry Jardin ◽  
Jean-Marc Moschetta

Convertible unmanned aerial vehicle (UAV) combines advantages of convenient autonomous launch/recovery and efficient long range cruise performance. Successful design of this new type of aircraft relies heavily on good understanding of powered lift generated through propeller-wing interactions, where the velocity distribution within propeller slipstream is critical to estimate aerodynamic forces during hover condition. The present research studied a propeller-wing combination with a plain flap. A 5-hole probe measurement system was built to construct three-dimensional (3D) velocity field at a survey plane after wing trailing edge. The study has found that significant deformation of propeller slipstream was present in the form of opposite transverse displacement on extrados and intrados. The deformation could be enhanced by flap deflections. Velocity differences caused by the slipstream deformation could imply local variation of lift distribution compared to predictions from conventional assumptions of cylindrical slipstream. An analytical method was developed to reasonably estimate the position of deformed slipstream centreline. The research underlined that the mutual aspect of propeller-wing interaction could be critical for low-speed aerodynamic design.


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