The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Michael L Banner - One of the best experts on this subject based on the ideXlab platform.
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the influence of wave breaking on the Surface Pressure Distribution in wind wave interactions
Journal of Fluid Mechanics, 1990Co-Authors: Michael L BannerAbstract:In reviewing the current status of our understanding of the mechanisms underlying wind-wave generation, it is apparent that existing theories and models are not applicable to situations where the sea Surface is disturbed by breaking waves, and that the available experimental data on this question are sparse. In this context, this paper presents the results of a detailed study of the effects of wave breaking on the aerodynamic Surface Pressure Distribution and consequent wave-coherent momentum flux, as well as its influence on the total wind stress. Two complementary experimental configurations were used to focus on the details and consequences of the Pressure Distribution over breaking waves under wind forcing. The first utilized a stationary breaking wave configuration and confirmed the presence of significant phase shifting, due to air flow separation effects, between the Surface Pressure and Surface elevation (and slope) Distributions over a range of wind speeds. The second configuration examined the Pressure Distribution, recorded at a fixed height above the mean water Surface just above the crest level, over short mechanically triggered waves which were induced to break almost continuously under wind forcing. This allowed a very detailed comparison of the form drag for actively breaking waves and for waves of comparable steepness just prior to breaking (‘incipiently’ breaking waves). For these propagating steep-wave experiments, the Pressure phase shifts and Distributions closely paralleled the stationary configuration findings. Moreover, a large increase (typically 100%) in the total windstress was observed for the breaking waves, with the increase corresponding closely to the comparably enhanced form drag associated with the actively breaking waves. In addition to further elucidating some fundamental features of wind-wave interactions for very steep wind waves, this paper provides a useful data set for future model calculations of wind flow over breaking waves. The results also provide the basis for a parameterization of the wind input source function applicable for a wave field undergoing active breaking, an important result for numerical modelling of short wind waves.
Aa Pashilkar - One of the best experts on this subject based on the ideXlab platform.
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Global response Surface model for unsteady Surface Pressures on delta wing aircraft AIAA Paper 2002-0711
2020Co-Authors: Aa PashilkarAbstract:The approximate Surface Pressure Distribution on the leeward Surface of a delta wing/body model has been estimated for static conditions and unsteady motions about the pitch axis. The Surface Pressure is estimated from the normal force and pitching moment characteristics. The model parameters are chosen based on a study of the Surface Pressure Distribution on simple delta wings. This model is useful as a first approximation of the load Distribution on the aircraft wing. The Pressure parameters are used to generate a global response Surface for generalization to arbitrary maneuvers about the pitch plane.
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Surface Pressure Estimates for Pitching Aircraft Model at High Angles-of-attack (Short Communication)
Defence Science Journal, 2002Co-Authors: Aa PashilkarAbstract:The Surface Pressure on a pitching delta wing aircraft is estimated from the normal force and the pitching moment characteristics. The Pressure model is based on parametrising the Surface Pressure Distribution on a simple delta wing. This model is useful as a first approximation of the load Distribution on the aircraft wing. Leeward Surface Pressure Distributions computed by this method are presented.
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Surface Pressure Estimates for Pitching Aircraft Model at High Angles-of-attack13; 13;
2002Co-Authors: Aa PashilkarAbstract:The Surface Pressure on a pitching delta wing aircraft is estimated from the normal force and the pitching moment characteristics. The Pressure model is based on parametrising the Surface Pressure Distribution on a simple delta wing. This model is useful as a first approximation of the load Distribution on the aircraft wing. Leeward Surface Pressure Distributions computed by this method are presented.
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Surface Pressure model for simple delta wings at high angles of attack
Sadhana, 2001Co-Authors: Aa PashilkarAbstract:A new aerodynamic modelling approach is proposed for the longitudinal static characteristics of a simple delta wing. It captures the static variation of normal force and pitching moment characteristics throughout the angle of attack range. The Pressure model is based on parametrizing the Surface Pressure Distribution on a simple delta wing. The model is then extended to a wing/body combination where body-alone data are also available. The model is shown to be simple and consistent with experimental data. The Pressure model can be used as a first approximation for the load estimation on the delta wing at high angles of attack.
M. Vezza - One of the best experts on this subject based on the ideXlab platform.
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Simulation of parallel blade–vortex interaction using a discrete vortex method
Aeronautical Journal, 1999Co-Authors: Ling Qian, M. VezzaAbstract:Numerical results are presented for two-dimensional vortex-aerofoil interaction using a grid-free discrete vortex method. The effects of the passing vortex on the Surface Pressure Distribution and hence the aerodynamic force and moment of the aerofoil are examined in detail for a variety of interaction geometries. For some head-on interaction cases, vortex-induced local flow separation is also predicted on the aft part of the aerofoil Surfaces
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Simulation of Parallel Blade-Vortex Interaction using a Discrete Vortex Method. G.U. Aero Report no. 9832
1998Co-Authors: Ling Qian, M. VezzaAbstract:Numerical results are presented for two-dimensional vortex-aerofoil interaction using a grid-free discrete vortex method. The effects of the passing vortex on the Surface Pressure Distribution and hence the aerodynamic force and moment of the aerofoil are examined in detail for a variety of interaction geometries. For some head-on interaction cases, vortex-induced local flow separation is also predicted on the aft part of the aerofoil Surfaces. Extensive comparisons are made with other numerical results and the results from the Glasgow University BVI windtunnel test, which show good agreement.
Kozo Fujii - One of the best experts on this subject based on the ideXlab platform.
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mechanisms of Surface Pressure Distribution within a laminar separation bubble at different reynolds numbers
Physics of Fluids, 2015Co-Authors: Soshi Kawai, Masayuki Anyoji, Hikaru Aono, Akira Oyama, Keisuke Asai, Taku Nonomura, Kozo FujiiAbstract:Mechanisms behind the Pressure Distribution and skin friction within a laminar separation bubble (LSB) are investigated by large-eddy simulations around a 5% thickness blunt flat plate at the chord length based Reynolds number 5.0 × 103, 6.1 × 103, 1.1 × 104, and 2.0 × 104. The characteristics inside the LSB change with the Reynolds number; a steady laminar separation bubble (LSB_S) at the Reynolds number 5.0 × 103 and 6.1 × 103, and a steady-fluctuating laminar separation bubble (LSB_SF) at the Reynolds number 1.1 × 104, and 2.0 × 104. Different characteristics of Pressure and skin friction Distributions are observed by increasing the Reynolds number, such that a gradual monotonous Pressure recovery in the LSB_S and a plateau Pressure Distribution followed by a rapid Pressure recovery region in the LSB_SF. The reasons behind the different characteristics of Pressure Distributions at different Reynolds numbers are discussed by deriving the Reynolds averaged Pressure gradient equation. It is confirmed that the viscous stress Distributions near the Surface play an important role in determining the formation of different Pressure Distributions. Depending on the Reynolds numbers, the viscous stress Distributions near the Surface are affected by the development of a separated laminar shear layer or the Reynolds shear stress. In addition, we show that the same analyses can be applied to the flows around a NACA0012 airfoil.
Craig Meskell - One of the best experts on this subject based on the ideXlab platform.
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Surface Pressure Distribution survey in normal triangular tube arrays
Journal of Fluids and Structures, 2009Co-Authors: John Mahon, Craig MeskellAbstract:Abstract As a first step towards a validation database for models of fluidelastic instability, an experimental parametric study of the Surface Pressure on a cylinder in the third row of three normal triangular tube arrays ( P / d = 1.32 , 1.58 and 1.97) with air cross flow has been performed. A range of static tube displacements were examined. Forces were calculated from the Pressure measurements providing an understanding of the force generation mechanism. The results show that the fluid forces do not scale proportionally with dynamic head. However, no simple parameterisation was found for the lift force. A bistable flow instability was observed in the pitch ratio of 1.58 even when the tube was displaced. This phenomena resulted in the large asymmetry observed in the Pressure Distribution around a static cylinder. It is concluded that the fluid forces which are related to fluidelastic instability are dependent on Reynolds number and pitch ratio.