Streamwise Body Force Model(SBFM)could be used to simulate the force of blade on the airflow,resulting in rapid propulsion-airframe integrated simulation.However,when subjected to inlet distortion,the upstream flow fi...Streamwise Body Force Model(SBFM)could be used to simulate the force of blade on the airflow,resulting in rapid propulsion-airframe integrated simulation.However,when subjected to inlet distortion,the upstream flow field of fan stage is redistributed,which causes inaccurate prediction of fan stage performance.As inspired by the upstream influence of compressor,this paper aims to present a modification strategy for SBFM method to predict the compressor performance under circumferential inlet distortion without any knowledge of compressor geometry.Based on the linearized motion equation,the Upstream Influence Model(UIM)is introduced to predict the upstream flow field redistribution.Then the theoretical Mach number at Aerodynamic Interface Plane(AIP)position is calculated and selected to determine the corresponding body force coefficients based on the functional relationship between body force coefficients and Mach number,thus the upstream influence of compressor could be accurately quantified and the Modified Streamwise Body Force Model(MSBFM)could be established.Two studied cases are calculated with different methods and the upstream flow fields are analyzed.The prediction error of MSBFM method for compressor adiabatic efficiency is less than 3%,and the calculation efficiency is improved 20 times under the condition of ensuring computing accuracy.The MSBFM method has the potential for rapid propulsion-airframe integrated simulation.展开更多
The choice of fulcrums for control of socio-economic systems represented by direc ted weighted signed graphs is a topic of current interest.This article proposes a new method for identifying nodes of impact and influe...The choice of fulcrums for control of socio-economic systems represented by direc ted weighted signed graphs is a topic of current interest.This article proposes a new method for identifying nodes of impact and influential nodes,which will provide a guaranteed positive system response over the growth model.The task is posed as an optimization problem to maximize the ratio of the norms of the accumulated increments of the growth vector and the exogenous impact vector.The algorithm is reduced to solving a quadratic programming problem with nonlinear restrictions.The selection of the most effective vertices is based on the cumulative gains of the component projections onto the solution vector.Numerical examples arc provided to illustrate the effectiveness of the proposed method.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52176032,51976005 and 52006002)the Advanced Jet Propulsion Creativity Center,China(No.HKCX2020-02-013)+2 种基金the National Science and Technology Major Project,China(Nos.2017-II-0004-0016 and 2017-II-0005-0018)the Fundamental Research Funds for the Central Universities,Chinathe Beijing Nova Program,China。
文摘Streamwise Body Force Model(SBFM)could be used to simulate the force of blade on the airflow,resulting in rapid propulsion-airframe integrated simulation.However,when subjected to inlet distortion,the upstream flow field of fan stage is redistributed,which causes inaccurate prediction of fan stage performance.As inspired by the upstream influence of compressor,this paper aims to present a modification strategy for SBFM method to predict the compressor performance under circumferential inlet distortion without any knowledge of compressor geometry.Based on the linearized motion equation,the Upstream Influence Model(UIM)is introduced to predict the upstream flow field redistribution.Then the theoretical Mach number at Aerodynamic Interface Plane(AIP)position is calculated and selected to determine the corresponding body force coefficients based on the functional relationship between body force coefficients and Mach number,thus the upstream influence of compressor could be accurately quantified and the Modified Streamwise Body Force Model(MSBFM)could be established.Two studied cases are calculated with different methods and the upstream flow fields are analyzed.The prediction error of MSBFM method for compressor adiabatic efficiency is less than 3%,and the calculation efficiency is improved 20 times under the condition of ensuring computing accuracy.The MSBFM method has the potential for rapid propulsion-airframe integrated simulation.
基金supported by the Russian Foundation for Basic Research (No. 17-01-00076)
文摘The choice of fulcrums for control of socio-economic systems represented by direc ted weighted signed graphs is a topic of current interest.This article proposes a new method for identifying nodes of impact and influential nodes,which will provide a guaranteed positive system response over the growth model.The task is posed as an optimization problem to maximize the ratio of the norms of the accumulated increments of the growth vector and the exogenous impact vector.The algorithm is reduced to solving a quadratic programming problem with nonlinear restrictions.The selection of the most effective vertices is based on the cumulative gains of the component projections onto the solution vector.Numerical examples arc provided to illustrate the effectiveness of the proposed method.
