An effective dynamic moving mesh algorithm suitable for multiblock parallel unsteady flow calculations using body fitted grids is presented in this paper. The moving grid algorithm within each block uses a method of arc-length based transfinite interpolation which is performed independently on local processors where the blocks reside. A spring network approach is used to determine the motion of the corner points of the blocks which may be connected in an unstructured fashion in a general multi-block method. A smoothing operator is applied to the points of the block face boundaries and edges in order to maintain grid smoothness and grid angles. A multi-block parallel Euler/Navier-Stokes solver using multigrid and dual-time stepping is developed along with the moving mesh method. Computational results are presented for the unsteady flow calculations of airfoils and wings with deforming shapes as found in flutter simulations.
The multiple-input and multiple-output (MIMO) channel model is very useful for the presentation of a wide range of wireless communication systems. This paper addresses the joint design of a precoder and a receiver for a point-to-point MIMO channel model in a scenario in which perfect channel state information (CSI) is available at both ends. We develop a novel framework for the dual transmission-reception process. Under the proposed framework, the receiver decomposes the channel matrix by using a block QR decomposition, where Q is a unitary matrix and R is a block upper triangular matrix. The optimal maximum likelihood (ML) detection process is employed within each diagonal block of R. Then, the detected block of symbols is substituted and subtracted sequentially according to the block QR decomposition based successive cancellation. On the transmitting end, the expression of probability of error based on ML detection is chosen as the design criterion to formulate the precoder design problem. This paper presents a design of MIMO transceivers in the particular case of having 4 transmitting and 4 receiving antennas with full CSI knowledge on both sides. In addition, a closed-form expression for the optimal precoder matrix is obtained for channels satisfying certain conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.