Periodic velocity inlet and dynamic mesh boundary conditions are always used to simulate oscillatory piston of synthetic jet. condition is an easy way oscillation membrane jet, a realistic method using moving grid the motion piston, but it needs more computing time because updating new topology at every step. In this paper, two methods' influence for jet simulation investigated, cases with different conducted respectively in low Reynolds number laminar flow. The results show that profiles...

Abstract The energy consumption of office buildings is analysed, and the influential factors to be considered in architectural design that affect light heat environment are summarised. original building model was established by Ecotect, variable methods were adopted simulate influence different influencing on thermal environment, quantitatively evaluate importance buildings. This analysis provides an important basis for optimised saving design, finally puts forward optimal strategy saving,...

The influence of trailing edge deformation on the aerodynamic characteristics camber morphing wings is an important topic in aviation field. In this paper, a new memory alloy actuator proposed to realize deformation, and computational fluid dynamics (CFD) wind tunnel experiments are used study wings. was carried out transonic with Mach numbers ranging from 0.4 0.8 angles attack 0° 6°. external flow fields force coefficients without were calculated using CFD method. A loose coupled method...

Local floating coordinate system is used to represent the deployment motion of each rigid and flexible body multibody dynamics. Normal substructure modes are employed describe flexibility a body. Constraint equations establish linkage between different bodies, part them specify positions others orientations. System's governing then derived using generalized coordinates by Lagrange methods. The resulting differential-algebraic transformed algebraic backward differential formula corrector...

The body freedom flutter characteristics of an airfoil and a fly wing aircraft model were calculated based on CFD method for the Navier–Stokes equations. Firstly, rigid elastic coupling dynamic two-dimensional with free–free boundary condition was derived in inertial frame decoupled by mode mode. In fluid–solid method, trimmed subtracting generalized steady aerodynamic force from structural equation. predicted variable stiffness at fixed Mach number flight altitude. Finally, validation...

In order to address the test requirements of small thrust liquid rocket engines with a broad combustion chamber pressure range, an automatic tank pressurization system for ground is designed and segmented comparison decision algorithm this developed. Both are validated by using simulation method during design phase. The mainly consists group right-angle orifice plates electromagnetic pneumatic valves, propellant tank, pipes, pipe fittings. key parts valves which enable provision gas at...

Diffuser performance prediction plays a crucial role in high-altitude simulation test of rocket engines. This paper presents study focused on calculating and applying the cylindrical diffuser's starting performance, aiming to provide straightforward efficient approach for characteristic curve, which reveals relationship between combustion chamber pressure ratio vacuum ratio. The curve can be understood as representing three operational stages, consisting 4 distinct feature points. To achieve...

This study proposes a computational fluid dynamics and structure (CFD/CSD) coupled method for calculating the buffet response of variant tail wing. The large-scale separated flow in is simulated by detached vortex approach, vibration deformation wing solved dynamic mesh generation technique, structural modeling based on mode method. aerodynamic elastic coupling calculated through cyclic iteration aerodynamics solution time domain. We verify correctness proposed typical delta calculation...

This article takes the National College Student Smart Car Competition as background and designs produces an electromagnetic tracking car based on STC32 chip. On basis of not violating competition rules, in order to improve running stability speed car, hardware uses a DRV8701E driver board drive motor four-inductor arrangement collect inductance signal; algorithm ratio Fuzzy PID handles values. The experimental results show that has good effect strong anti-interference ability, can...

This paper presents a CFD/CSD coupling method for aeroelastic simulation of folding tail morphing aircraft. The unsteady aerodynamic analysis is based on an in-house computational fluid dynamics (CFD) solver the Euler equations, and emphasis made developing efficient dynamic mesh tail’s hybrid fold motion/elastic vibration deformation. structural (CSD) technique solving equation motion in modal space. was achieved through successive iterations CFD CSD computations time domain. An adaptive...

In order to improve aerodynamic efficiency and obtain large lift-drag ratio, unmanned aerial vehicles with high altitude long endurance usually have wing aspect ratio flexibility, resulting in static aeroelastic deformation up 25% of half-extension. Therefore, aerostatic-elastic influencing factors must be included the design objective. development stage aircraft, research mainly relies on wind tunnel test numerical calculation. For tests, elastic model focuses meeting requirements...

The mechanical load of wind turbine is complicated and changeable under the imbalanced fault wheel, which intensifies influence fatigue on service life main components generation quality turbine. mechanism model change established. Aiming at caused by two phenomena mass imbalance aerodynamic imbalance, time domain characteristics top tower drum are analyzed GH Bladed simulation software to identify characteristic parameters. results show that cases will lead increase limit turbine, destroy...

Diamond back wing is subjected to large deformation while gliding, which significantly changes characteristics of the lift as well static stability. For this reason, conventional rigid aircraft assumption cannot meet requirements aerodynamic analysis such aircrafts for accuracy. In paper, based on CFD/CSD methods, aeroelasticity a small diameter bomb with diamond was studied. The results showed that aeroelastic effects cause slope line drop by 21% and centre move backwards 1.5% body length,...

Abstract For some flying-wing aircraft with large aspect ratio, the pitching inertia is small, which makes longitudinal short-period modal frequency higher. Structural flexibility 1st bending mode lower. This of rigid body easily coupled elastic mode, resulting in aeroelastic instability, called freedom flutter. There are many factors affecting flutter characteristics. The and structural characteristics fuselage wing all have an impact on it. Taking airfoil as example, dynamics model system...

The capacity of modern cellular wireless networks is mainly limited by inter-cell interference (ICI).Coordinated multi-point (CoMP) transmission and reception were adopted as key techniques for Long Term Evolution-Advanced (LTE-A) they are capable mitigating ICI through cooperation between several cell sites.Therefore, CoMP provide a significant improvement in cell-edge average throughput.For downlink CoMP, most research work focuses on joint processing/transmission (CoMP-JP) mode.However...

To address the contradiction between convergence error and rate in LMS algorithm, this study proposes a variable-step-size adaptive filter algorithm with momentum term based on logistic function. First, normalization is obtained by seeking extremum under Lagrange function constraint. Second, to reduce of model used as step size variation error, resulting variable-step algorithm. Our experimental results demonstrate that achieves smaller errors compared those traditional Finally, further...

A new type of gust generator generates the airflow oscillation in wind tunnel through Coanda effect unsteady trailing edge blowing, which has been shown to have strong potential for accurately simulating discrete gusts. It is necessary study relationship between generated characteristics and control parameters such devices order optimize design performance improve simulation capabilities. By solving compressible Reynolds-averaged Navier–Stokes (URANS) equations, computational fluid dynamics...

Abstract The optimization problem of aeroelastic wing model may lead to highly coupled nonlinear equations whose Jacobian matrix is hard be calculated, followed by adjusting the variable domain due design importance in terms their sensitivity. To overcome problem, an function for modal frequency established. And a suitable line search approach combined with BFGS method improve its efficiency. Some numerical results are reported show efficiency proposed method. An integrated based on...

In this paper, the measurement method of compliance coefficient is briefly introduced, and flexibility experiment carried out. The test results show that structural symmetry wing static aeroelastic model good, error matrix less than 2%.

In order to reduce the flow resistance on surface of ships, skin with quasi-periodic elastic supports is designed based flexible drag reduction technology inspired by dolphin skin. this paper, stability characteristic equation fluid-structure coupling system established small perturbation theory and solved MATLAB. The results indicate that has ability maintaining turbulent boundary layer when structural parameters are reasonable. addition, performance studied immersion method. analysis...