Numerical study on the effect of a downstream braking plate on the detailed flow field and unsteady aerodynamic characteristics of an upstream braking plate with or without a crosswind

2020 ◽  
pp. 1-18 ◽  
Author(s):  
Jiqiang Niu ◽  
Yueming Wang ◽  
Feng Liu ◽  
Rui Li
Keyword(s):  
Flow Field ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Unsteady Aerodynamic

The Numerical Study of a New Air-Cooled Turbine Blade With Depression Feature at Leading Edge

2008 ◽  
Author(s):  
Songtao Wang ◽  
Kai Wang ◽  
Xiaoqing Qiang ◽  
Zhongqi Wang
Keyword(s):  
Flow Field ◽  
Energy Loss ◽  
Turbine Blade ◽  
Pressure Field ◽  
Numerical Study ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Air Injection ◽  
Blade Profile ◽  
Cooling Air

A new air-cooled turbine blade with depression feature at leading edge was presented in this paper. The flow field of this blade at the transonic condition was simulated in detail. The change of vortex position induced by the leading edge cooling air injection along the blade profile was observed. The aerodynamic characteristics of the new blade such as film effectiveness, energy loss, pressure field etc. were compared with the traditional air-cooled turbine blade. The result shows that this new blade locks the vortex induced by the leading edge cooling air injection in its depression part. The mixing of cooling air and mainstream becomes weak. Thus, the number of the leading edge cooling air injection holes can be reduced. Correspondingly, the amount of injection can also be reduced.

Numerical study on the effect of damaged windows on aerodynamic characteristics of passenger trains under strong crosswind

2020 ◽  
Vol 234 (15) ◽  
pp. 2994-3003 ◽  
Author(s):  
Jiqiang Niu ◽  
Yueming Wang ◽  
Feng Liu
Keyword(s):  
Flow Field ◽  
Numerical Study ◽  
Lateral Force ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Windward Side ◽  
Leeward Side ◽  
Strong Wind ◽  
Passenger Vehicle ◽  
Overturning Moment

Sand and gravel blown up by strong wind will cause damage to windows. Following up, it will cause the change in the flow field around a train immediately, which has a significant impact on the aerodynamic performance of the train. Delayed detached-eddy simulation based on the shear stress transport κ-ω turbulence model was used to investigate the aerodynamic characteristics of passenger vehicles under crosswind, and the effect of damaged windows on the train aerodynamic performance and flow field around the train was analyzed and compared. The grid generation and numerical method are verified in the previous studies. Results show that the aerodynamic performance of a passenger vehicle is significantly affected by damaged windows on both sides of the passenger vehicle, both the aerodynamic lateral force and overturning moment of the passenger vehicle were decreased, and this has a small effect on the aerodynamic performance of the downstream passenger vehicle. Fluctuation of the aerodynamic lift, lateral force, and overturning moment of a vehicle with damaged windows on both sides of the vehicle is significantly increased. Damaged windows do not change the existence of the main vortices around vehicles, but the size, location, and strength of the main vortices are obviously changed, especially when windows on both sides of the vehicle are damaged. Therefore, when windows on the windward side of the vehicles are damaged, opening or broking windows on the leeward side of the vehicles will help reduce the risk of vehicles overturning and derailment.

A comprehensive numerical study of battle damage and repairs upon the aerodynamic characteristics of an aerofoil

2010 ◽  
Vol 114 (1158) ◽  
pp. 469-484 ◽  
Author(s):  
M. Saeedi ◽  
F. Ajalli ◽  
M. Mani
Keyword(s):  
Flow Field ◽  
Numerical Solution ◽  
Mesh Generation ◽  
Unstructured Mesh ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
The Other ◽  
Stall Angle

Abstract A NACA 641-412 aerofoil with circle and star damage and also three repair configurations has been numerically investigated. Two different methods of mesh generation were employed: multi structured mesh for the star damaged aerofoil and unstructured mesh for the other aerofoils. The results show that the damage will cause a reduction in lift coefficient of the aerofoil and also a different stall angle relative to that of the undamaged aerofoil. Each kind of repair improves the aerodynamic characteristics of the aerofoil considerably. The flow Field inside the damage hole and the cavity caused by the repair sheets was also investigated. Finally, the numerical solution was qualitatively and quantitatively validated using the available experimental results.

Numerical Study of the Combined Free-Forced Convection and Mass Transfer Flow Past a Vertical Porous Plate in a Porous Medium with Heat Generation and Thermal Diffusion

2006 ◽  
Vol 11 (4) ◽  
pp. 331-343 ◽  
Author(s):  
M. S. Alam ◽  
M. M. Rahman ◽  
M. A. Samad
Keyword(s):  
Mass Transfer ◽  
Flow Field ◽  
Differential Equations ◽  
Forced Convection ◽  
Heat Generation ◽  
Numerical Study ◽  
Porous Plate ◽  
Integration Scheme ◽  
Suction Parameter ◽  
Transfer Flow

The problem of combined free-forced convection and mass transfer flow over a vertical porous flat plate, in presence of heat generation and thermaldiffusion, is studied numerically. The non-linear partial differential equations and their boundary conditions, describing the problem under consideration, are transformed into a system of ordinary differential equations by using usual similarity transformations. This system is solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with Runge-Kutta sixth order integration scheme. The effects of suction parameter, heat generation parameter and Soret number are examined on the flow field of a hydrogen-air mixture as a non-chemical reacting fluid pair. The analysis of the obtained results showed that the flow field is significantly influenced by these parameters.

Numerical study of geometric morphing wings of the 1303 UCAV

2021 ◽  
pp. 1-17
Author(s):  
B. Nugroho ◽  
J. Brett ◽  
B.T. Bleckly ◽  
R.C. Chin
Keyword(s):  
Flight Control ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Morphing Wing ◽  
Rolling Moment ◽  
Wide Range ◽  
Morphing Wings ◽  
Wing Geometry ◽  
Lift And Drag ◽  
Wing Morphing

ABSTRACT Unmanned Combat Aerial Vehicles (UCAVs) are believed by many to be the future of aerial strike/reconnaissance capability. This belief led to the design of the UCAV 1303 by Boeing Phantom Works and the US Airforce Lab in the late 1990s. Because UCAV 1303 is expected to take on a wide range of mission roles that are risky for human pilots, it needs to be highly adaptable. Geometric morphing can provide such adaptability and allow the UCAV 1303 to optimise its physical feature mid-flight to increase the lift-to-drag ratio, manoeuvrability, cruise distance, flight control, etc. This capability is extremely beneficial since it will enable the UCAV to reconcile conflicting mission requirements (e.g. loiter and dash within the same mission). In this study, we conduct several modifications to the wing geometry of UCAV 1303 via Computational Fluid Dynamics (CFD) to analyse its aerodynamic characteristics produced by a range of different wing geometric morphs. Here we look into two specific geometric morphing wings: linear twists on one of the wings and linear twists at both wings (wash-in and washout). A baseline CFD of the UCAV 1303 without any wing morphing is validated against published wind tunnel data, before proceeding to simulate morphing wing configurations. The results show that geometric morphing wing influences the UCAV-1303 aerodynamic characteristics significantly, improving the coefficient of lift and drag, pitching moment and rolling moment.

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