A new method based on the anisotropic tensor force finite element and Taylor-Galerkin finite element is presented in the present paper.Its application to two-dimensional viscous transonic flow in turbomachinery improv...A new method based on the anisotropic tensor force finite element and Taylor-Galerkin finite element is presented in the present paper.Its application to two-dimensional viscous transonic flow in turbomachinery improves the conver- gence rate and stability of calculation,and the results obtained agree well with the experimental measurements.展开更多
A family of variational principles (VP) has been developed for the unsteady inverse problem of the second type I B. It opens new ways for the inverse shape design of unsteady airfoils and can serve as key basis of m...A family of variational principles (VP) has been developed for the unsteady inverse problem of the second type I B. It opens new ways for the inverse shape design of unsteady airfoils and can serve as key basis of multipoint inverse shape design of steady airfoils and cascades.展开更多
Based on the author’s previous work, a general form of generalized variational princi-ples (VPs) together with its derived VP family is established for 3-D unsteady’ transonicpotential flow with shocks past arbitrar...Based on the author’s previous work, a general form of generalized variational princi-ples (VPs) together with its derived VP family is established for 3-D unsteady’ transonicpotential flow with shocks past arbitrary wings oscillating periodically. To facilitate thenumerical handling, full use is made of functional variations with variable domain and natu-ral boundary conditions (BC) so that almost all boundary/interface conditions, including theRankine-Hugoniot shock relations and slip conditions across free trailing vortex sheets, havebeen converted into natural ones. Also distributed suction/blowing along the wing surfacefor the boundary layer control is accounted for. This theory aims at rendering a general,rigorous theoretical basis for the finite element metbod and other direct variational methods,and it can be generalized to both wing-body combinations and 3-D rotating bladings, includ-ing the subsonic flow as a special case.展开更多
A new kind of Universal Serendipity Element (USE) - the Tensor Universal Serendipity Element (TUSE) is constructed by using both tensor force finite elements and the basic idea of USE. The formulation of shape functio...A new kind of Universal Serendipity Element (USE) - the Tensor Universal Serendipity Element (TUSE) is constructed by using both tensor force finite elements and the basic idea of USE. The formulation of shape functions and their derivatives for TUSE is presented. TUSE can be used to study steady and unsteady transonic flow fields when combined with Taylor-Galerkin Finite Element Methods, the NND scheme in FDM, and four-stage Runge-Kutta methods. As numerical examples the transonic flow in cascades and one kind of complex unsteady transonic axisymmetric how in engineering are studied. It is shown that the algorithm presented in this paper is efficient and robust.展开更多
Hierarchical evolutionary algorithms based on genetic algorithms (GAs) and Nash strategy of game theory are proposed to accelerate the optimization process and implemented in transonic aerodynamic shape optimization p...Hierarchical evolutionary algorithms based on genetic algorithms (GAs) and Nash strategy of game theory are proposed to accelerate the optimization process and implemented in transonic aerodynamic shape optimization problems Inspired from the natural evolution history that different periods with certain environments have different criteria for the evaluations of individuals’ fitness, a hierarchical fidelity model is introduced to reach high optimization efficiency The shape of an NACA0012 based airfoil is optimized in maximizing the lift coefficient under a given transonic flow condition Optimized results are presented and compared with the single model results and traditional GA展开更多
An implicit upwind finite volume solver for the Euler equations using the improved flux - splitting method is established and used to calculate the transonic flow past the airfoils with heaving, pitching oscillations ...An implicit upwind finite volume solver for the Euler equations using the improved flux - splitting method is established and used to calculate the transonic flow past the airfoils with heaving, pitching oscillations and the control surface. Results are given for the NACA64A - 10 airfoil which is in harmonic heaving and pitching oscillation and with the control surface in the transonic flow field. Some computational results are compared with the experiment data and the good agreements are shown in the paper.展开更多
文摘A new method based on the anisotropic tensor force finite element and Taylor-Galerkin finite element is presented in the present paper.Its application to two-dimensional viscous transonic flow in turbomachinery improves the conver- gence rate and stability of calculation,and the results obtained agree well with the experimental measurements.
文摘A family of variational principles (VP) has been developed for the unsteady inverse problem of the second type I B. It opens new ways for the inverse shape design of unsteady airfoils and can serve as key basis of multipoint inverse shape design of steady airfoils and cascades.
文摘Based on the author’s previous work, a general form of generalized variational princi-ples (VPs) together with its derived VP family is established for 3-D unsteady’ transonicpotential flow with shocks past arbitrary wings oscillating periodically. To facilitate thenumerical handling, full use is made of functional variations with variable domain and natu-ral boundary conditions (BC) so that almost all boundary/interface conditions, including theRankine-Hugoniot shock relations and slip conditions across free trailing vortex sheets, havebeen converted into natural ones. Also distributed suction/blowing along the wing surfacefor the boundary layer control is accounted for. This theory aims at rendering a general,rigorous theoretical basis for the finite element metbod and other direct variational methods,and it can be generalized to both wing-body combinations and 3-D rotating bladings, includ-ing the subsonic flow as a special case.
基金The project supported by the National Natural Science Foundation of China
文摘A new kind of Universal Serendipity Element (USE) - the Tensor Universal Serendipity Element (TUSE) is constructed by using both tensor force finite elements and the basic idea of USE. The formulation of shape functions and their derivatives for TUSE is presented. TUSE can be used to study steady and unsteady transonic flow fields when combined with Taylor-Galerkin Finite Element Methods, the NND scheme in FDM, and four-stage Runge-Kutta methods. As numerical examples the transonic flow in cascades and one kind of complex unsteady transonic axisymmetric how in engineering are studied. It is shown that the algorithm presented in this paper is efficient and robust.
基金Start-up foundation item of the Educational Department of China for returnees
文摘Hierarchical evolutionary algorithms based on genetic algorithms (GAs) and Nash strategy of game theory are proposed to accelerate the optimization process and implemented in transonic aerodynamic shape optimization problems Inspired from the natural evolution history that different periods with certain environments have different criteria for the evaluations of individuals’ fitness, a hierarchical fidelity model is introduced to reach high optimization efficiency The shape of an NACA0012 based airfoil is optimized in maximizing the lift coefficient under a given transonic flow condition Optimized results are presented and compared with the single model results and traditional GA
文摘An implicit upwind finite volume solver for the Euler equations using the improved flux - splitting method is established and used to calculate the transonic flow past the airfoils with heaving, pitching oscillations and the control surface. Results are given for the NACA64A - 10 airfoil which is in harmonic heaving and pitching oscillation and with the control surface in the transonic flow field. Some computational results are compared with the experiment data and the good agreements are shown in the paper.
