We derive equations and study nonlinear dynamics of cascade two-photon laser, in which the electromagnetic field in the cavity is driven by coherently prepared three-level atoms and classical field injected into the c...We derive equations and study nonlinear dynamics of cascade two-photon laser, in which the electromagnetic field in the cavity is driven by coherently prepared three-level atoms and classical field injected into the cavity. The, dynamic equations of such a system are derived by using the technique of quantum Laugevin opera.tots, and then arre studied numerically under different driving＂ conditions, The results show that trader certain conditions the cascade twophoton laser can generate chaotic, period doubling, periodic populations, atomic coherences, and injected classical field, stable and bistable states. Chaos can be inhibited by atomic In ,addition, no chaos occurs in optical bista.bility.展开更多
Based on control theory,adjoint system for the general problem of turbomachinery aerodynamic optimization was studied and developed in the present paper by using the variation technique in the grid node coordinates co...Based on control theory,adjoint system for the general problem of turbomachinery aerodynamic optimization was studied and developed in the present paper by using the variation technique in the grid node coordinates combined with Jacobian Matrics of flow fluxes.Then the adjoint system for aerodynamic design optimization of turbine cascade governed by compressible Navier-Stokes equations was derived in detail.With the purpose of saving computation resources,the mathematic method presented in this paper avoids the coordinate system transforming in the traditional derivation process of the adjoint system and makes the adjoint system much more sententious.Given the general expression of objective functions consisting of both boundary integral and field integral,the adjoint equations and their boundary conditions were derived,and the final expression of the objective function gradient including only boundary integrals was formulated to reduce the CPU cost,especially for the complex 3D configurations.The adjoint system was solved numerically by using the finite volume method with an explicit 5-step Runge-Kutta scheme and Riemann approximate solution of Roe's scheme combined with multi-grid technique and local time step to accelerate the convergence procedure.Finally,based on the aerodynamic optimization theory in the present work,2D and 3D inviscid and viscous inverse design programs of axial turbomachinery cascade for both pressure distribution and isentropic Mach number distribution on the blade wall were developed,and several design optimization cases were performed successfully to demonstrate the ability and economy of the present optimization system.展开更多
基金The project partially supported by Natural Science Foundation of Jiangsu Province of China under Grant No. BK2005062
文摘We derive equations and study nonlinear dynamics of cascade two-photon laser, in which the electromagnetic field in the cavity is driven by coherently prepared three-level atoms and classical field injected into the cavity. The, dynamic equations of such a system are derived by using the technique of quantum Laugevin opera.tots, and then arre studied numerically under different driving＂ conditions, The results show that trader certain conditions the cascade twophoton laser can generate chaotic, period doubling, periodic populations, atomic coherences, and injected classical field, stable and bistable states. Chaos can be inhibited by atomic In ,addition, no chaos occurs in optical bista.bility.
基金supported by the National Natural Science Foundation of China (Grant No. 50776065)
文摘Based on control theory,adjoint system for the general problem of turbomachinery aerodynamic optimization was studied and developed in the present paper by using the variation technique in the grid node coordinates combined with Jacobian Matrics of flow fluxes.Then the adjoint system for aerodynamic design optimization of turbine cascade governed by compressible Navier-Stokes equations was derived in detail.With the purpose of saving computation resources,the mathematic method presented in this paper avoids the coordinate system transforming in the traditional derivation process of the adjoint system and makes the adjoint system much more sententious.Given the general expression of objective functions consisting of both boundary integral and field integral,the adjoint equations and their boundary conditions were derived,and the final expression of the objective function gradient including only boundary integrals was formulated to reduce the CPU cost,especially for the complex 3D configurations.The adjoint system was solved numerically by using the finite volume method with an explicit 5-step Runge-Kutta scheme and Riemann approximate solution of Roe's scheme combined with multi-grid technique and local time step to accelerate the convergence procedure.Finally,based on the aerodynamic optimization theory in the present work,2D and 3D inviscid and viscous inverse design programs of axial turbomachinery cascade for both pressure distribution and isentropic Mach number distribution on the blade wall were developed,and several design optimization cases were performed successfully to demonstrate the ability and economy of the present optimization system.
