Numerical simulation of splashing landing gear on an amphibious aircraft air cushion

This paper is aimed at researching the interaction between aeroacoustic noise radiated from a rectangular cavity (gear bay) and from landing gear. It is a complicated flow-induced noise problem, involving the nonlinear, unsteady evolution of the turbulent structure inside the airflow bypassing the landing gear and the cavity. The generation and radiation mechanism of aeroacoustic noise are also concerned. In fact, it is a problem about the nonlinear interaction between the vortices shedding from the boundary layer of bluff bodies and the cavity-limited shear layer. To simplify this issue, a two-wheel landing gear named LAGOON is chosen as the landing gear model. The unsteady flow field and aerodynamic noise from it is simulated by applying the commercial software ANSYS Fluent. Good agreement is achieved between the numerical simulation and wind tunnel measurements in terms of the aerodynamic and aeroacoustic results. According to the size of LAGOON, a simple rectangular cavity is designed as the landing gear bay. Both the cavity combined with LAGOON and the cavity alone are simulated and compared. The results show that under the blocking effect of a strut, most small pieces of vortices at the trailing edge of the cavity bottom would dissipate rather than move forward along with the backflow, leading to the correlation of cavity resonance being more contrasting and increasing its amplitude. The blockage effect induced by rear wall could also enhance the turbulence kinetic energy at the wake of the strut, thus increasing the low-frequency noise radiated from the strut and cavity.

Download Full-text

A Semi-Active Controller for an Aircraft Landing Gear Equipped with Magnetorheological Damper

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.894.29 ◽

2019 ◽

Vol 894 ◽

pp. 29-33

Author(s):

Luong Quoc Viet ◽

Jai Hyuk Hwang

Keyword(s):

Numerical Simulation ◽

Force Control ◽

Hybrid Control ◽

Mr Damper ◽

Landing Gear ◽

Operating Conditions ◽

Magnetorheological Damper ◽

Numerical Simulation Result ◽

Aircraft Landing ◽

Aircraft Landing Gear

The magnetorheological (MR) damper is the newest approach to replace the traditional passive damper which cannot change their dynamics in response to different operating conditions of the aircraft landing gear. This paper presents the simulation study of a semi-active controller for a landing gear equipped MR damper. Furthermore, a new method combined skyhook control with force control, called hybrid control, is developed to improve the performance of the MR damper landing gear. Finally, the numerical simulation result of the landing gear using SIMSCAPE-Simulink is discussed.

Download Full-text

Optimization of Groove-Hole Distribution with Equidistant and Unequal Diameter on Air-Cushion Belt Conveyor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.44-46.635 ◽

2008 ◽

Vol 44-46 ◽

pp. 635-642

Author(s):

J.F. Li ◽

Suo Long Zhang

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Research And Development ◽

Cross Section ◽

Flow Model ◽

Optimal Parameters ◽

Belt Conveyor ◽

Air Cushion ◽

Fluent Software ◽

Air Hole

In this paper, the research and development of the distribution of air-holes in the groove of air-cushion belt conveyor were introduced. The expressions of air-cushion pressure were given and the graph of it was shown as well. The air flow model nearby groove-holes and air outflow model on cross section were given too. In the same time, the distributing mode of equidistant air-holes with unequal diameter was studied and analyzed. In order to make up the shortage of the study on air-hole distributing mode of equidistant air-holes with unequal diameter on the air-cushion belt conveyor, an instance of the air-cushion flow field was numerically simulated based on the CFD software ,Fluent software. Several groups of data of different air-hole distributions, (for example, the center distances of air-holes in the groove of air-cushion belt conveyor are the same as each other and their diameters are different), were selected to compare with each other , and then, the results were compared with existing theory. According to the different results of the numerical simulation on the distributing mode of equidistant air-holes with unequal diameter, the optimal parameters of air-hole distributing mode were obtained, and the effect of prevent offset that comes the balance groove-hole on air-cushion belt conveyor. Moreover, the verification to prove the agreement between the results of numerically simulated and basic theory was carried out by the comparison analyses. The theoretical feasibility of air-hole distributing mode of equidistant air-holes with unequal diameter was analyzed.

Download Full-text