نتایج جستجو برای: aerodynamic control

تعداد نتایج: 1338692  

2010
P. S. Sreetharan R. J. Wood

Flapping-wing robotic platforms based on Dipteran insects have demonstrated lift to weight ratios greater than 1, but research into regulating the aerodynamic forces produced by their wings has largely focused on active wing trajectory control. In an alternate approach, a flapping-wing drivetrain design that passively balances aerodynamic drag torques is presented. A discussion of the dynamic p...

2005
David A. Neal Harry Robertshaw

This work describes the design and construction of a fully adaptive aircraft configuration used as an experimental testbed for aerodynamic modeling and flight control. The adaptive model is designed to achieve large scale shape changes in order to investigate morphing for multi-mission UAVs. There are five independent planform changes along with independent twist control for each wing. Wind tun...

2004
Ho Chul Lee Jae Weon Choi Yong Seok Choi

This paper is concerned with the control allocation strategies with the two-time scale dynamic inversion which generate nominal control input trajectories. In addition, an robust flight control design method is proposed by using a time-varying control technique which is a timevarying version of the pole placement of the linear time-invariant system for an agile missile with aerodynamic fin, thr...

1993
Hans Georg Bock Klaus Lesch Marc Steinbach

Fuel minimum range cruise of aircraft with high aerodynamic ef-ciency is considered as an optimal periodic control problem. Optimality conditions for trajectories with singular arcs and state variable constraints are derived. Computation of periodic optimal trajectories in the case addressed presents strong requirements on the numerical algorithm. Computational diiculties become larger when aer...

2015
Wen-Li Chen Yong Cao Hui Li Hui Hu

This paper numerically investigates the effectiveness of the control of steady suction on a stationary circular cylinder with several isolated suction holes on the surface at a subcritical Reynolds number. The control effectiveness as a function of the azimuthal position, spanwise spacing and suction flow rate of the suction holes on the control of the aerodynamic forces on the cylinder and the...

2015
David Lentink Andreas F. Haselsteiner Rivers Ingersoll

Flapping wings enable flying animals and biomimetic robots to generate elevated aerodynamic forces. Measurements that demonstrate this capability are based on experiments with tethered robots and animals, and indirect force calculations based on measured kinematics or airflow during free flight. Remarkably, there exists no method to measure these forces directly during free flight. Such in vivo...

2014

Most birds and many insects use periodic wing motion to propel themselves and maneuver. Most conventional flying machines are propelled by rotating machinery, achieve lift through rotating or fixed wings, and are controlled through the production of steady aerodynamic forces produced by rotors or movable wings. Many of the first powered flapping-wing micro air vehicles (MAVs) effectively replac...

Journal: :علوم و فناوری فضایی 0
s. ghasemloo s. noori

in this paper, an approximate axisymmetric method is developed which can reliably calculate fully viscous hypersonic flow over blunt-nosed bodies. in this method, a maslen’s second-order pressure expression is used instead of the normal momentum equation. the combination of maslen’s second-order pressure expression and viscous shock layer equations is developed to accurately and efficiently com...

Aerodynamic drag is an important factor in vehicles fuel consumption. Pressure drag which is the main component of total drag is a result of boundary layer separation from vehicle surface. Flow control methods are applied to avoid or at least delay separation. Depending upon whether these methods consume energy to control the flow or not, they are called active or passive control methods. In th...

The purpose of this paper is to present a fast, economical and practical method for mathematical modeling of aerodynamic characteristics of rectangular wing-in-ground effect (WIG). Reynolds averaged Navier-Stokes (RANS) equations were converted to Bernoulli equation by reasonable assumptions. Also Helmbold's equation was developed for calculation of the slope of wing lift coefficient in ground ...

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