The buffeting pressure field of a high-aspect-ratio swept wing

1985 ◽  
Author(s):  
F. ROOS
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Pressure Field ◽  
Swept Wing

The Effect of Structural Geometric Nonlinearities on the Flutter of the Straight and Swept Wing Configurations

2012 ◽  
Vol 189 ◽  
pp. 306-311 ◽  
Author(s):  
Qing Guo ◽  
Bi Feng Song
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Swept Wing ◽  
Geometric Nonlinearities ◽  
Air Vehicle ◽  
Structural Nonlinearity ◽  
Flutter Analysis ◽  
Long Endurance ◽  
The Impact ◽  
Straight Wing

High altitude and long endurance (HALE) vehicle always adopt straight or swept configuration, which leads to the problem that the wings of UAV have high aspect ratio and are very flexible. This kind of flexible wing exhibits large deformation when aerodynamic forces are loaded on them and the structural nonlinearity should be considered. So the dynamic and flutter characteristics will be changed. In the engineering applications, the effects of structural geometric nonlinearities on the air vehicle design are the most concerns of aeroelasticity before a systematic flutter analysis for the air vehicle. because the solution for nonlinear flutter speed based on the CFD-CSD method is complex and time consuming. In this paper, we propose a simple and efficient approach that can analyze the effect of structural geometric nonlinearities on the flutter characteristics of high aspect ratio wing quickly. And a straight wing and a straight-swept wing are analyzed to verify the feasibility and efficiency of the proposed method. It is found that the effect of structural geometric nonlinearities has a strong effect on the flutter characteristic of the straight wing, but is weak on the straight-swept wing. And finally the impact of swept angle on the dynamic and flutter characteristics of straight-swept wing is also discussed.

scholarly journals Numerical Investigation into Flutter and Flutter-Buffet Phenomena for a Swept Wing and a Curved Planform Wing

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Mario Rosario Chiarelli ◽  
Salvatore Bonomo
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Sensitivity Study ◽  
Fuel Saving ◽  
Swept Wing ◽  
Instability Condition ◽  
Aspect Ratios ◽  
Numerical Studies ◽  
Classical Flutter

The results of numerical studies carried out on high-aspect-ratio wings with different planforms are discussed: the transonic regime is analysed for a swept wing and a curved planform wing. The wings have similar aspect ratios and similar aerodynamic profiles. The analyses were carried out by CFD and FE techniques, and the reliability of the numerical aerodynamic results was proven by a sensitivity study. Analysing the performances of the two wings demonstrated that in transonic flight conditions, a noticeable drag reduction can be obtained by adopting a curved planform wing. In addition, for such a wing, the aeroelastic instability condition, consisting in a classical flutter, is postponed compared to a conventional swept wing, for which a flutter-buffet instability occurs. In a preliminary manner, the study shows that, for a curved planform wing, the high speed buffet is not an issue and at the same time notable fuel saving can be achieved.

On the Derivation of Pressure Field Distribution at the Entrance of a Rectangular Capillary

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Prashant R. Waghmare ◽  
Sushanta K. Mitra
Keyword(s):  
Aspect Ratio ◽  
Field Distribution ◽  
High Aspect Ratio ◽  
Pressure Field ◽  
Capillary Flow ◽  
Control Volume ◽  
Equivalent Radius ◽  
Circular Capillary ◽  
Entrance Pressure ◽  
Correct Expression

In capillary flow, integral momentum approach is used to derive the governing equation, which requires an expression for the pressure field at the inlet of the capillary. Generally, the pressure field for circular capillary is deduced with hemispherical control volume. This expression has been extended for other noncircular capillaries with an equivalent radius approximation. In case of high aspect ratio channels, the semicylindrical control volume needs to be considered. In the present study, the correct expression for the entrance pressure field for high aspect ratio capillaries is derived with such appropriate control volume.

The Effect of a Translating High Aspect Ratio Particle in a Plane Slider Bearing

1983 ◽  
Vol 105 (3) ◽  
pp. 396-404 ◽  
Author(s):  
M. T. Languirand ◽  
J. A. Tichy
Keyword(s):  
Aspect Ratio ◽  
Theoretical Analysis ◽  
High Aspect Ratio ◽  
Pressure Field ◽  
Stokes Equations ◽  
Velocity Fields ◽  
Two Dimensional ◽  
Slider Bearing ◽  
Experimental Apparatus ◽  
Initial Starting

An approximate solution of Stokes equations is presented to determine the pressure and velocity fields in an infinite slider bearing containing a two-dimensional high aspect ratio particle of arbitrary cross-section. The particle may translate in two directions as well as rotate about its centroid. The fluid field is divided into four regions: upstream, above, below, and downstream of the particle. The governing Stokes equations are applied to each region and solved through specific continuity requirements and pressure matching conditions. For illustrative purposes, this method of analysis is applied to a plane slider bearing containing a rectangular particle which can translate in one direction. Approximate solutions are given for the pressure and velocity fields. The solution reveals a pressure drop which develops in the pressure field at the particle location. The magnitude of this drop is shown to be dependent on a particle size, velocity, and location. It is shown that the particle has a major effect on the bearing pressure field when it is able to significantly obstruct the flow of the lubricant. To support the theoretical analysis, experimental research is performed. An experimental apparatus is used to measure the transient pressure in a slider bearing as a high aspect ratio two-dimensional rectangular particle is passed through the fluid film. The apparatus measures pressure at a particular location in the bearing and simultaneously measures the particle’s displacement with respect to its initial starting location. Results are given to demonstrate the effect of particle velocity on the pressure field in the bearing. The experimental results presented are in good agreement with analytical results obtained from the theoretical analysis.

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