Forward Variable Area Bypass Injector(FVABI)is one of key components which contributes to modulate the cycle parameters of Variable Cycle Engine(VCE)under various operation conditions.The modeling method of zero-dimen...Forward Variable Area Bypass Injector(FVABI)is one of key components which contributes to modulate the cycle parameters of Variable Cycle Engine(VCE)under various operation conditions.The modeling method of zero-dimensional FVABI was reviewed and its deficiency was analyzed based on FVABI flow characteristic.In order to improve the accuracy of VCE performance simulation,the high-fidelity modeling method of FVABI was developed based on its working characteristics.Then it was coupled with the zero-dimensional VCE model and the multi-level VCE model was built.The results indicate that the geometric and aerodynamic parameters can affect the interaction between the two airflows and the zero-dimensional FVABI model is too simple to predict the component performance accurately,especially when the FVABI inner bypass is chocked.Based on the performance curves for single bypass mode and the regression model of multi-scale support vector regression for double bypass mode,the high-fidelity model can predict FVABI performance accurately and rapidly.The integration of high-fidelity FVABI model into zerodimensional VCE model can be done by adjusting iterative variables and balance equations.The multi-level model has good convergence and it can predict VCE performance when the FVABI inner bypass is chocked.展开更多
This paper studies limit behaviors of stationary measures for stochastic ordinary differential equations with nondegenerate noise and presents a criterion to guarantee that a repeller with zero Lebesgue measure is a n...This paper studies limit behaviors of stationary measures for stochastic ordinary differential equations with nondegenerate noise and presents a criterion to guarantee that a repeller with zero Lebesgue measure is a null set of any limit measure.Using this criterion,we first provide a series of nontrivial concrete examples to show that their repelling limit cycles or quasi-periodic orbits are null sets for all limit measures,which deduces that all their limit measures are concentrated on stable equilibria and stable limit cycles or quasi-periodic orbits,and saddles.Interesting open questions on exact supports of limit measures are proposed.展开更多
基金the financial support of the National Natural Science Foundation of China(Nos.51876176 and 51906204)。
文摘Forward Variable Area Bypass Injector(FVABI)is one of key components which contributes to modulate the cycle parameters of Variable Cycle Engine(VCE)under various operation conditions.The modeling method of zero-dimensional FVABI was reviewed and its deficiency was analyzed based on FVABI flow characteristic.In order to improve the accuracy of VCE performance simulation,the high-fidelity modeling method of FVABI was developed based on its working characteristics.Then it was coupled with the zero-dimensional VCE model and the multi-level VCE model was built.The results indicate that the geometric and aerodynamic parameters can affect the interaction between the two airflows and the zero-dimensional FVABI model is too simple to predict the component performance accurately,especially when the FVABI inner bypass is chocked.Based on the performance curves for single bypass mode and the regression model of multi-scale support vector regression for double bypass mode,the high-fidelity model can predict FVABI performance accurately and rapidly.The integration of high-fidelity FVABI model into zerodimensional VCE model can be done by adjusting iterative variables and balance equations.The multi-level model has good convergence and it can predict VCE performance when the FVABI inner bypass is chocked.
基金supported by National Natural Science Foundation of China(Grant Nos.11771295,11431014,11931004 and 11371252)Key Laboratory of Random Complex Structures and Data Science,Academy of Mathematics and Systems Science,Chinese Academy of Sciences(Grant No.2008DP173182)。
文摘This paper studies limit behaviors of stationary measures for stochastic ordinary differential equations with nondegenerate noise and presents a criterion to guarantee that a repeller with zero Lebesgue measure is a null set of any limit measure.Using this criterion,we first provide a series of nontrivial concrete examples to show that their repelling limit cycles or quasi-periodic orbits are null sets for all limit measures,which deduces that all their limit measures are concentrated on stable equilibria and stable limit cycles or quasi-periodic orbits,and saddles.Interesting open questions on exact supports of limit measures are proposed.
