Flows past a rotating circular cylinder at high Reynolds number are investigated by a discrete vortex method. The nascent vortices are introduced to the flowfield at each time step from several points uniformly distributed around and near the surface of the circular cylinder. Calculations are performed for ω=0.5, and 1.0, where ω is the angular velocity of rotation and equals the specific speed, i.e., the ratio of the peripheral velocity to the uniform flow velocity in this case. The results agree qualitatively well with experimental results. The reverse Magnus effect, however, due to the transitions of the boundary layers on the upper side and the lower side of the circular cylinder did not appear, and the simulation for this by the present method seems to be difficult.
This paper presents an theoretical analysis of the elastic bending wave propagation in a rotating fan blade by the use of a simplified model. An impact of constant lateral force or constant moment is subject to a semi-infinite elastic beam at the end. Constant body force which represents the centrifugal force due to the rotation is acting parallel to the initial beam direction. The result of the analysis shows that a similar solution for the bending wave exists in case of no centrifugal force. The wave velocity and the moment are obtained in a simple form. The centrifugal force effects the decrease of the wave velocity and the amplitude of the bending moment.
Two types of model, which describes the human monitoring behabior in failure detection task are proposed in this paper. In the first model, detection behavior of human monitor is modeled by two linear optimal estimator (Kalman filter); the failure detection mechanism in the model is based on Wald's Sequential Probability Ratio Test (SPRT). The second model is composed of two fundamental function, that are, linear predictor using autoregressive model and Wald's SPRT. Digital simulations are carried out for checking on the accuracy of proposed models and illustrating the procedure to predict monitor's performance. The simulation results of detection time (the time needed for detecting the failure) and detection accuracy (frequency of miss and/or false alarm) are compared with data obtained from a set of failure detection experiments. From these comparison, it is found that the models can explain adequately the essential characteristics of human operator performing the monitoring task, and also important information for system failure detection by human monitor is rate of visual perception signal. The second model will be applied to a study of failure detection by human controller in a further paper.
By introducing ACT (Active Control Technology), the resulting aircraft is able to do "new ways to fly" and is defined as CCV (Control Configured Vehicle). As such an aircraft is modelled as an MIMO system, its control law is commonly constructed by high gain P.I. plus gain scheduled method. But recently, an aircraft can fly over a wide range with its improved performance, and its derivatives can vary rapidly in flight. Therefore, except predefined points it is difficult to control such an aircraft satisfactorily. So, in this paper we proposed a design method of CCV adaptive flight control system with an unknown interactor matrix, the matrix is uniquely constructed from a controlled system and plays an important roll in producing the control law. Then, the proposed adaptive control system is applied to the small-sized and high speed aircraft with vertical canard and flap control surfaces, and by numerical simulations the effectiveness of the proposed method is examined.
The drag coefficient of a peripheral jet GEM depends considerably upon the ratio of free stream dynamic pressure to mean cushion pressure. In particular, the drag is significantly less than that evaluated by Chaplin's assumption (parasite drag+ momentum drag). Previously we clarified the existence of a horse-shoe vortex surrounding a GEM model from the bottom of which the air is supplied, and proved the generating mechanism of the "interference thrust". This paper presents a result of preliminary experiments about an intake effect on the GEM external drag. A built-in-fan model ("model 2") is tested in a wind tunnel, and the aerodynamic performance of this model is compared with one for previous model which has no intake ("model 1"). The configuration of model 2 is selected so that the separation of the momentum drag from the external drag may be as reasonable as possible. Both model are hemispherical.