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In this paper, the motion of partial air cushion support catamaran (PACSCAT) sailing in regular waves was firstly investigated by the experimental method. The monitored histories of heave, pitch, midship acceleration, and air cushion pressure in towing tests are performed to analyze the influence of air cushion on the periodicity feature of hull body motion. Subsequently, using the finite volume method (FVM)-based CFD software Star-ccm, numerical simulations are carried out for the PACSCAT model with a simplification of the air cushion system. The detailed flow information of wave evolution, pressure, and velocity distribution is investigated. The calculated oscillation characteristics of different motion parameters are compared with those from experiment and show good agreement. The numerical method also has good capacity in the prediction of amplitude response of heave and midship acceleration; however, large error is found when calculating resistance and amplitude response of pitch. [ABSTRACT FROM AUTHOR]

Automatic assembly with a part vibrating on incompressible air cushion is considered. The equation of pressure distribution in air cushion between the part and the supporting surface of a pneumatic track is derived. To solve the equation of pressure distribution, a finite element model is constructed. The equation of part motion on air cushion and the equation of pressure distribution are solved. The zones of parameter combinations of air flow and the part motion are defined in cases of slowly damping process, slowly increasing vibrations amplitude or constant amplitude vibrations of the part on the air cushion. Dependencies of vibrations amplitude and air cushion pressure, both on air flow and the system parameters are determined. [ABSTRACT FROM AUTHOR]

The mathematical model of the dynamics of an Air Cushion Vehicle with a ballonet type skirt is presented. This model incorporates a number of interrelated submodels representing different constituents of ship dynamics: rigid body, air cushion, propulsion system, ballonet, underlying surface, aerodynamics, yaw rudder. The proposed model is capable of predicting all major characteristics of the ship movement such as trajectory, forces, moments, air cushion pressure, subject to different operating conditions. Both controlled and uncontrolled movement may be simulated. The suggested approach is based on the numerical integration of the equations of motion as well as the equation describing the pressure evolution in the air cushion. The verification of the model was carried out and the results of model towing tests are presented. [ABSTRACT FROM AUTHOR]

The Partial Air Cushion Supported Catamaran (PACSCAT) is an innovative design which combines both the characteristics of hovercraft and catamaran. Further, it provides a high-speed and efficient solution with excellent performance, particularly for shallow water. In this paper, experimental and numerical method are carried out for research of motion attitude and resistance characteristics, which provide a reference for further research and hull optimization work. By model towing test and data interpretation, and the resistance, trim, and heave varying law with increasing speed is summarized. From the view of total resistance, the impacts of the cushion pressure and air flow on resistance performance of PACSCAT are analyzed. Based on the theory of viscous fluid mechanics, a numerical simulation method with high prediction accuracy is established. The flow field around and inside the hull is simulated, the simulating results show good agreements with the testing data. Finally, the effect of the cushion compartment improving the resistance performance is studied. The results show that the cushion compartment is significant for adjusting the pressure distribution of the air cushion. And the average resistance reduction ratio at the high-speed segment can even reach 22%. [ABSTRACT FROM AUTHOR]

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Presents information on a study which evaluated the pressure distribution of air cushions for patients with spinal cord injuries. Subjects and methods; Results and discussion; Conclusions.