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A flying wing possesses no definite fuselage and no horizontal tail surfaces resulting in lesser drag surfaces, a larger wing area with a better range and endurance as compared to a conventional unmanned aerial vehicle (UAV). The present work explores an efficient and stable flight of a flying wing UAV at a lower Reynolds number using backward facing step wing profile. Numerical simulations for flow...
This paper deal with stall warning system critical flight modes. Special focus was on critical conditions warning indication during landing. Recommendations about the basic parameters required for display warning critical conditions whilst landing was proposed.
Recently, the use of flexible structure in aerospace vehicles and micro-air vehicles are increased due to its ability to adapt to severe flow conditions; however; fully flexible structure has the risk to get damage in the case of long chord or high Reynolds number. In this work, a CFD analysis is carried out to study the influence of local flexible structure on the lift performance of airfoil. Single...
This paper uses wing characteristics from the Half Scale Unmanned Arial Vehicles (UAV) designed by Defence Technology Institute (DTI). It also demonstrates results from both plain wing and wing fitted with VGs simulation using a commercial Computational Fluid Dynamics (CFD) program. VGs designing processes (sizing and installed position) are also designed according to historical data. Furthermore,...
The performances of K-ω SST(Shear-Stress Transport) turbulence model and high order low dissipative Flux difference scheme of Roe are evaluated against experimental flow fields at different geometries and angle of attacks at supersonic mach no. The numerical predictions include lift, drag and pitching moment coefficients at different angle of attacks. Most significantly, this research provides a sensitivity...
The different shapes of reentry vehicle cone with different radii and cone half angle have been studied and verified with experimental data by using higher order low dissipative scheme of Harten and Yee. A code has been generated to simulate the flow at high Mach number and shock capturing technique has been used for the location of shock waves. The patterns of shock waves and aerodynamics performance...
The non-standard dynamics characteristics of hypersonic vehicles, the aerodynamic effects together with the wide range of speed and altitude during operation make modeling and control of these vehicles highly challenging. Modeling and analysis of hypersonic vehicles are important for control and navigation system design. A six degrees of freedom simulation model of the wing cone generic hypersonic...
The vertical load of aircraft is changing due to the lift along runway. Affected by traffic model of highway, load with fixed value is used as a design basis in present design theory of pavement and the effect of lift is generally expressed by lift coefficient. According to the Monte Carlo method, a Visual Basic program was written to simulate the operation of aircraft on runway. Accuracy of the simulation...
This paper presents the wind turbine emulator using the wind turbine model based on blade element momentum theory. The lift coefficient cl and drag coefficient cd of designed blade shape are calculated with the fluid analysis. Therefore the proposed wind turbine emulator can emulate the new designed windmill without manufacturing. Also the wind turbine model considers the mechanical model and the...
The two-dimensional incompressible Navier-Stokes equations and the SST k-?? turbulence model are used to investigate the aerodynamic performance of a wind turbine airfoil under clean and rough surface conditions. The DU 95-W-180 airfoil is analysized, which is widely used in wind turbines. The numerical simulation of the airfoil under clean surface condition is performed, and the numerical results...
In this paper, the hydrodynamic performances of unsteady flapping foil were studied by panel method based on potential flow theory. The flapping foil had a coupling motion of rolling and pitching. The calculation process of panel method was realized by the FORTRAN procedure. The calculation results of average thrust coefficient by the procedure accordance well with the MIT experiment data. Then the...
This work aims to study a two-dimensional incompressible flow around a cylinder in forced movement in order to understand the phenomena that occur in cylindrical structures under periodic oscillation using the Direct Numerical Simulation technique. The simulations were taken using the computational code named Incompact3d. It was used the Reynolds Number as 400 in all simulations. The trajectories...
The laminar-to-turbulent transition is one of the most complex but important flows. In order to deeply apprehend the wind turbine airfoil flow characteristics and the transition phenomenon, a two-equation transition model is applied in this article to simulate the flow over a wind turbine S814 airfoil. Typical angle of attack and both steady and unsteady transition models are tried. The predictions...
Reynolds number has a direct impact on the performance of a wind turbine aerofoil. In this paper, the airfoil NREL S809 was chosen for the research, using numerical simulation and experiment for the performance of the two-dimensional aerodynamic airfoil flow. While Reynolds number varies from 1.5times104 to 2times105, both the drag coefficient and the lift coefficient have great changes. However,...
The 2-D airfoil of the wind turbine (NREL S809) was experimentally and numerically studied. The experiment focused on the PIV measurement of the 2-D airfoil flow field with different angles of attack under various Reynolds numbers. A lot of important and useful information was obtained. Furthermore, the experimental result was compared with CFD simulation in order to study the flow field in more detail,...
Since about ten years, dielectric barrier discharge (DBD) was studied as electro-hydrodynamic (EHD) actuator for airflow control. A DBD surface discharge generates nonthermal plasma allowing to modify the boundary layer of airflow. The active control enables fast action on airflow. A thin flexible asymmetric DBD actuator was used in our study, each elementary DBD was made with two copper electrodes...
This paper describes the drag coefficient and the lift coefficient of Darrieus type turbines, and also discusses accuracy of numerical calculations of Darrieus type water turbines with computational fluid dynamics (CFD) comparing with some results of model experiments by us. Corresponding Darrieus turbines are a vertical blade type. Objectives of this study are to investigate follows: 1) characteristics...
A closed-loop control system has been developed and tested for tracking prescribed values of aerodynamic force on a NACA 4412 airfoil. The system includes a measurement-based estimator - utilizing a low-dimensional model of the perturbation flow based on the method of proper orthogonal decomposition - and a stochastic correlation between the measurement and the state estimate. The system employs a...
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