Vol. 3, No. 4 (2019): Regular Issue

The flow about a circular cylinder placed within a channel is studied numerically in order to examine the lift forces on the cylinder for Reynolds numbers below the onset of unsteady flow. It is observed that there is a critical Reynolds number between 60 and 80 that results in the lift force to become destabilizing for the cylinder equilibrium position at the center of the channel. Meanwhile, two new equilibrium positions of the cylinder away from the channel center come to existence. Associated with this bifurcation of the equilibria, the flow streamline and vorticity plots are presented.

This study first constructed the information system, and monitored the key technical parameters of the brewing process in real time. The neural network was used to construct the fermented grains model, and the online evaluation of the fermentation process was realized according to the real-time fermentation parameters. The intelligent batching system adjusted the ratio of the fermented grains, grains and other materials according to the evaluation result. The robot used infrared thermal imaging technology to perform the steamerfilling operation. The application results showed that the technology had a positive effect on improving the yield and quality of Chinese Baijiu.

In this paper, the stability and bifurcation of equilibriums in low-degree polynomial systems are discussed. Appearing and switching bifurcations of simple and higher order equilibriums are discussed, and such bifurcations of equilibriums are not only for simple equilibriums but for higher-order equilibriums. The 3rd-order sink and source bifurcations for simple equilibriums are presented. The 3rd-order sink and source switching bifurcations for saddle and nodes are discovered, and the 4th-order upper-saddle and lower-saddle switching and appearing bifurcations are obtained for two 2nd-order upper-saddles and two 2nd-order lower-saddles, respectively. Graphical illustrations of global stability and bifurcations are presented.

In the recent decades, the accuracy and robust of finite state inflow model to provide the velocity on the disk have been greatly improved. It is adequate to compute the thrust, pitch and roll moment real time for normal flight conditions. For lifting rotor flying close to a non-penetrable surface, the wake will interact with the inflow of the lifting rotor. Additionally, for co-axial rotors the wake of the upper rotor influences the lower rotor. Therefore, it is necessary to develop a model to compute the flow field in the wake since the Peters-He model cannot give the induced velocity below the rotor disk. In this paper, the improved finite state model will be introduced to compute the axial induced velocity everywhere in the flow field including wake and downstreamregions. The adjoint theorem will be introduced, and the computational efficiency of the convolution method and numerical algorithm for computing the adjoint varibales with time delay will be compared. With the parameters of a Harrington rotor, the results in the time domain for such a rotor in hover and forward flight conditions will also be illustrated.

In this paper, we present the search problem formulated as a decision making problem, the search agent decides whether the target is present in the search region, and if so, where it is located. Then we propose a sequential decision-making framework for a search agent to find a lost target within a bounded region with the searcher motion constraints and imperfect observations being considered. This framework enables the theoretical study to the evolution of the search decision, then we propose two effective adaptive search strategies, which have the advantage of requiring less computation than traditional search strategy. Simulation results shows that the proposed adaptive search strategies have a better performance. Finally, the proposed control strategies are analyzed from different perspectives in detail.

In this note, we establish the existence, uniqueness and stability of a special class of fractional pantograph equation with Atangana- Baleanu fractional derivative(ABFD). The arguments are based upon Schauder fixed point theorem and Banach contraction principle. In addition, we discuss the stability results of proposed equation by the concept of Ulam. At last an example is given to illustrate the theory.