For the quad tilt rotor aircraft, a computational fluid dynamics method based on multiple reference frames (MRF) was used to analyze influence of aerodynamic layout parameters characteristics aircraft. Firstly, numerical simulation for interference flow field aircraft is established. Based this method, isolated rotors, combinations at different lateral positions wing, and rotation directions under inflow velocities were calculated analyzed, in order grasp their laws provide design control...

The tilt-wing aircraft has attracted widespread attention due to its excellent performance. However, aerodynamic characteristics during the tilt transition section are characterized by unsteadiness, nonlinearity, and strong coupling, making it difficult control. Using computational fluid dynamics (CFD) methods moving overset grids control motion, momentum source method is employed replace actual propellers. influence of propeller on tiltrotor at different angles investigated under incoming...

Abstract The dragonfly flapping flight as a kind of important model, in order to explore the aerodynamic effect on forewing flapping. Based real wings(with corrugation 3D forewing), this paper uses X-flow software numerical simulation for analyzed influence different flow velocity and frequency dragonfly. When flies forward stably, results show that it has higher lift with increase inflow frequency. leading edge vortex (LEV) dragonfly’s does not fall off period, maximum positive is generated...

A program for calculating the aerodynamic properties of hypersonic vehicles based on surface element method was developed using general-purpose programming language C++. The calculated values lift coefficients, drag and pressure coefficients are discussed with results wind tunnel experiments HL-20 body NASA aircraft STS Columbia OV-102 as research subjects. Finally, experimental studies characteristics at an altitude 65 km Mach numbers 6 10 Ma discussed. maximum error in does not exceed 3%,...

A low-complexity adaptive tracking control strategy for a class of pure feedback nonlinear systems is developed in the presence completely unknown non-affine nonlinearities, prescribed performance constraints, full states and input saturation constraint. To handle nonlinearity constrained without pre-calculating bound virtual controllers, new coordinate transformation approach presented with an arc-tangent function auxiliary first-order dynamics. Subsequently, to deal nonlinearities problem...

The hydrodynamics in fish school are studied through simulating the flow over two wiggling hydrofoils diagonal arrangement by using immersed boundary method, both in-phase and anti-phase motions considered this study, effect of longitudinal spacing on hydrodynamic performance has been investigated. It is revealed that, when smaller than body length, formation helpful to follower but harmful leader; larger opposite occurring; a significant enhancement propulsive obtained optimized.

Abstract In order to study the aerodynamic performance of dragonfly forewing-hindwing interaction in gliding flight, three-dimensional (3D) model with corrugation forewing and hindwing are established. This paper studied effects at motion using method computational fluid dynamics (CFD) for angles attack changing from 0° 25°(with an interval 5°). Numerical simulation indicates that interactions between enhance both varying degrees compared independent wings, especially effect is more evident...

Gliding flight is a common mode of for dragonfly, the objective current research to use numerical simulations explore whether corrugations have positive effect on aerodynamic performance dragonfly wings in gliding flight. In order compare wing and flat plate, three-dimensional model forewing plate with same shape are established. The flow fields around simulated Re=10000 angles attack changing from 0° 25°(with an interval 5°), simulation indicate that slightly better than over entire range...

Abstract To investigate the influence of flexible distribution on aerodynamic characteristics a dragonfly hind wing during flapping flight, this study establishes simplified plate model based actual size, while neglecting wrinkled microstructure. Six different patterns are proposed for model. The overlapping grid technique is employed to achieve fluid-structure coupling calculations motion wing, by customizing Young’s modulus in solid region represent levels flexibility. results show that...

Abstract In this study, the full free motion of filament in vortex structures is numerically simulated, and influence model parameters horizontal position on propulsion efficiency investigated. With “data + physics” approach with immersed boundary method Random Forest (RF) method, an RF initially employed to screen 189 sets numerical experiments using a minimal amount flow field physical data select experimental groups capable generating bands. The selected are then used complete...

Fish employ their bodies and caudal fins to generate a counter-propagating traveling wave, which, in conjunction with the surrounding fluid dynamics, results propulsion pattern that is both rapid efficient. From mathematical perspective, these waves can be represented as waves. This study focuses on simulating kinematic state of NACA65-010 self-propelled hydrofoil, operating under low Reynolds number uniform incoming flow, utilizing immersed boundary method. Additionally, we investigate...