Dynamic Behaviour of Attaching Jet

The dynamic behaviour of attaching jet with single side wall to step control flow and the switching proces of the bistable amplifiers were investigated experimentally and theoretically. In the experiments, a large scale model was used with water. The flow patterns were visualized by the tracer of polystrene granules and were recorded by a cinecamera. In the analysis, the quasi-steady proces was assumed. The results obtained can be summarized as follows: 1) The proposed analytical dynamic model of attaching jet explains well the dynamic behaviour of attaching jet with single side wall. 2) The process" of the opposite wall switching may be divided into three phases. 3) The analytical model of the opposite wall switching, including the formulation of the switching criterion, was proposed

Dynamic Switching of Wall-Reattachment Fluidic Device

Effect of the geometrical configuration of wall-reattachment fluidic device on the switching dynamics, the switching time, and its dispersion, was investigated experimentally by using a large scale model. The results obtained can be summarized as follows: 1) The switching time, its dispersion, and switching probability depend upon the connection of the input to the control port. 2) Effect of the vent and splitter on the jet in dynamic switching is explained commonly by using the margin of a given control flow rate to the switching control flow rate. 3) The switching time ,decreases as input increases, whereas its dispersion remains constant except for small input

カリュウケイ ダイオードナイ サンジゲン ナガレ ノ スウチ ジッケン

In this paper, by means of numerical experiment, the transient response of the flow in the vortex diode and the steady flow field in the vortex chamber are investigated in detail. The flow in the chamber is regarded as an unsteady, three-dimensional, incompressible and viscous flow. The primitive Navier-Stokes equations are solved by using p-u method. The calculated vortex diode consists of four tangential nozzles, a square vortex chamber and an exit nozzle. The results obtained can be summaried as follows : 1) In the transient reverse flow, two distinct stages are recognized as known in the physical experiment. The significant pressure drop in the chamber occurs at the second stage when the rotating flow is accelerated. 2) In the steady reverse flow, the radial velocity in the end wall boundary layers is larger than that at midplane. Therefore, the most fluid particles flows out of the chamber through the end wall region. 3) The diode ratio, which has never been known theoreticaly, can be predicted by calculating the forward flow field too

アクティブ エア サスペンション ノ セイシン セイノウ コウジョウ ノタメノ セイギョホウ ニ カンスル ケンキュウ

It is important to improve both the ride quality and the driving stability of vehicles. However, with conventional passive suspensions, these two requirements can rarely be simultaneously satisfied. In this paper, an active air suspension is constructed using a pneumatic cylinder and two electro pneumatic proportional pressure control valves, which has the advantage of inherent buffer function due to the air compressibility. However, an electro pneumatic control valve involves a considerable delay time which deteriorates the vibration control performance. To cope with this problem, the control valve delay is formulated as an input time delay in the discrete-time state equation, for which an optimal regulator with a state observer is designed. Through experiments, the applicability of this optimal control method for the active air suspension can be confirmed

パーソナル コンピュータ オ モチイタ ニジュウ トウリツ フリコ ノ アンテイカ セイギョ

It is the purpose of this paper to design and realize the digital control system which can stabilize a double inverted penpulum in order to use a penumatic motor as an actuater instead of an electric motor in the next step of this study. A double inverted pendulum is a typical unstable mechanical system and is much more difficult to be controlled than a single inverted pendulum. The system consists of a double pendulum, a cart, electric motor and a personal computer PC-9801VX. The results obtained can be summarized as follows : 1) By inserting a model compensator between a servo amplifier and a D/A converter, the nonlineality due to the saturation of an amplifier can be reduced and a double inverted pendulum can be stabilized. Such a compensator is very useful to design a control system by using a high response motor with the servo amplifier because a linear control theory can be applied easily. 2) When a cart speed and angular velocities of pendulum are estimated by differentiating the displacement and angles respectively, a double pendulum can be kept stand invertedly even though a cart rattles because of a low resolution encoder. 3) When an optimal observer is added to the control system, a double inverted pendulum can not be stabilized for a long time, but a cart can move smoothly. This is caused by mainly the coulomb friction which exists in the shaft of the upper pendulum

オン オフ デンジベン ニヨル リュウリョウ セイギョ

In this paper, the motion of the spool and the flow rate of a spring return solenoid valve drived by PWM method have been analyzed theoretically and experimentally. The conditions to get the desired relationship between the flow rate and the pulse duty cycle have been predicted and these conditions have been confirmed by experiments. The obtained results are summerizd as follows : 1) In order to get the proportional flow rate corresponding to the pulse duty cycle, it is necessary that the solenoid thrust decreases and the spring force increases when the spool displacement increases. 2) In order to get the on-off flow rate characteristics, it is necessary for them to increase with an increase of the spool displacement. 3) Increasing the exciting pulse frequency, the proportional flow rate characteristics approaches to the on-off flow rate characteristics. In a practical valve used in experiment, the proportional characteristics were kept untill 50 Hz of the pulse

リュウタイ ソシナイ 3ジゲン ナガレ ノ スウチ ジッケン

In this paper, by means of the numerical experiment, the laminar jet behaviour in an attachment fluidic device with small aspect ratio is investigated. The numerical solution for the three-dimensional, imcompressible, unsteady and viscid flow is calculated by solving the primitive Navier-Stokes equations by use of the predictor-corrector method. The results obtained can be summarized as follows : 1. In the case of smaller aspect ratio, the numerical solution can be obtained to the extent of the higher Reynolds Number. 2. Near the bounding plates more fluid flows into the separation bubble than that at midplane and then this flows toward midplane, and finally is entrained by the main flow. 3. The flow along the side wall, also, enters the bubble near the bounding plates. This results in a longer attachment distance near the bounding plates

クウキアツ モータ オ モチイタ コウソク イチキメ セイギョ

There has been little study on the control system with pneumatic motors although pneumatic motors have some advantages : they are smaller and safer during times of overload than electric motors, cleaner than hydraulic motors and they have less effect of air compressibility than pneumatic cylinders because of smaller gass volume. The purpose of this study is to investigate whether pneumatic motors can be used in a high speed positioning. The pneumatic servo system tested in this study consists of a cart, a vane type or a radial piston type pneumatic motor, two electro-pneumatic proportional pressure control valves and a personal computer PC-9801RA. The results obtained can be summarized as follows. Posicast control scheme can give higher speed positioning than PID control scheme. The vane type pneumatic motor is better for a position control because its characteristics is not affected by a temperature compared to the radial piston type. The settling time of 0.6 second was obtained when the posicast position control was tested for the desired position of 1.4 m with the vane type motor. Thus we attained our desired end ; the average positioning speed higher than 2 m/s