For a graphlike manifold whose contraction is a generalized cuneate figure,we deribve a formula in this paper to compute the number of homeomorphism classes of it by using twist operations and the combinatorial theory.
In order to improve the analysis accuracy of the influence of shape parameters on the aerodynamic performance of cycloidal propeller,a set of CFD methods suitable for the simulation of the cycloidal propeller flow fie...In order to improve the analysis accuracy of the influence of shape parameters on the aerodynamic performance of cycloidal propeller,a set of CFD methods suitable for the simulation of the cycloidal propeller flow field based on the dynamic overset mesh and Unsteady Reynolds time average method equation were established.The characteristics of the spanwise lift distribution and surface pressure distribution in case of different negative twist were provided.The influence of the negative twist on the aerodynamic performance of cycloidal propeller was emphasized.The results showed that,the change of negative twist caused the change of azimuth for cycloidal propeller lift.The larger the absolute value of negative twist,the lower the figure of merit of the cycloidal propeller;the smaller the negative twist,the more gentle the instantaneous aerodynamic fluctuation;the influence mechanism of negative twist on the aerodynamic performance of cycloidal propeller was generated from changing the non-uniform distribution of the cycloidal propeller’s effective angle of attack.展开更多
文摘For a graphlike manifold whose contraction is a generalized cuneate figure,we deribve a formula in this paper to compute the number of homeomorphism classes of it by using twist operations and the combinatorial theory.
基金Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In order to improve the analysis accuracy of the influence of shape parameters on the aerodynamic performance of cycloidal propeller,a set of CFD methods suitable for the simulation of the cycloidal propeller flow field based on the dynamic overset mesh and Unsteady Reynolds time average method equation were established.The characteristics of the spanwise lift distribution and surface pressure distribution in case of different negative twist were provided.The influence of the negative twist on the aerodynamic performance of cycloidal propeller was emphasized.The results showed that,the change of negative twist caused the change of azimuth for cycloidal propeller lift.The larger the absolute value of negative twist,the lower the figure of merit of the cycloidal propeller;the smaller the negative twist,the more gentle the instantaneous aerodynamic fluctuation;the influence mechanism of negative twist on the aerodynamic performance of cycloidal propeller was generated from changing the non-uniform distribution of the cycloidal propeller’s effective angle of attack.
