This paper concerns the real time control of the boundary layer on an aircraft wing. This new approach consists in heating the surface in an unsteady regime using electrically resistant strips embedded in the wing ski...This paper concerns the real time control of the boundary layer on an aircraft wing. This new approach consists in heating the surface in an unsteady regime using electrically resistant strips embedded in the wing skin. The control of the boundary layer＇s separation and transition point will provide a reduction in friction drag, and hence a reduction in fuel consumption. This new method consists in applying the required thermal power in the different strips in order to ensure the desired temperatures on the aircraft wing. We also have to determine the optimum size of these strips （length, width and distance between two strips）. This implies finding the best mathematical model corresponding to the physics enabling us to facilitate the calculation for any type of material used for the wings. Secondly, the heating being unsteady, and, as during a flight the flow conditions or the ambient temperatures vary, the thermal power needed changes and must be chosen as fast as possible in order to ensure optimal operating conditions.展开更多
This paper presents some new dynamic interaction analysis approaches for square or non-square systems and a pairing evaluation method. For square stable systems, an open-loop approach is proposed, which features the t...This paper presents some new dynamic interaction analysis approaches for square or non-square systems and a pairing evaluation method. For square stable systems, an open-loop approach is proposed, which features the tradeoff between the contributions of response time constant and delay time to relative gain. For non-square stable systems, an extension from the proposed open-loop approach for square systems is presented and the corresponding pairing procedure is given. No interaction analysis approach is perfect for all systems, so any recommended pairing needs to be examined. An evaluation method is proposed in closed-loop with optimal controllers for each loop and whether the pairing is appropriate can be evaluated through testing if the equivalent relative gain is within defined scope. The advantages and effectiveness of proposed interaction analysis approaches and pairing evaluation method are highlighted via several examples of industrial processes.展开更多
The paper represents very simple procedure of identification, based on step response of the process. Results of identification are extended Strejc＇s models （named ZenanX model, models with n equivalent time constant...The paper represents very simple procedure of identification, based on step response of the process. Results of identification are extended Strejc＇s models （named ZenanX model, models with n equivalent time constants and delay time）. Described mathematically proved equations which show an easy way of filtering and differentiation step response with the help of the data window. It also supports the contention that the point of intersection of tangent to the integrated step response and the X axis represents the sum of time constants and delay time, and showed the method （named ZenoX method） of determining Strej c extended model. For the determination of the impulse response （important for definition of models） are used orthonormal functions （Laguerre）. Simulations are made in the package Matlab. The paper represents results from numerous simulations. The method allows simple and rapid extraction of the Extended Strejc model （ZenanX model）, which is often used to adjust the controllers. Through the simulations of the procedure of removing noise from measured step response is described.展开更多
The relaxation of a one-dimensional magnetic nanoparticle linear chain with lattice constant a is investigated in absence of applied field. There is an equilibrium state （or steady state） where a11 magnetic moments ...The relaxation of a one-dimensional magnetic nanoparticle linear chain with lattice constant a is investigated in absence of applied field. There is an equilibrium state （or steady state） where a11 magnetic moments of particles lie along the chain （x-axis）, back to which the magnetic nanoparticle chain at other state will relax. It is found that the relaxation time T= is determined by Tx = 10β×α3. This relaxation is compared with that of single magnetic nanoparticle system.展开更多
文摘This paper concerns the real time control of the boundary layer on an aircraft wing. This new approach consists in heating the surface in an unsteady regime using electrically resistant strips embedded in the wing skin. The control of the boundary layer＇s separation and transition point will provide a reduction in friction drag, and hence a reduction in fuel consumption. This new method consists in applying the required thermal power in the different strips in order to ensure the desired temperatures on the aircraft wing. We also have to determine the optimum size of these strips （length, width and distance between two strips）. This implies finding the best mathematical model corresponding to the physics enabling us to facilitate the calculation for any type of material used for the wings. Secondly, the heating being unsteady, and, as during a flight the flow conditions or the ambient temperatures vary, the thermal power needed changes and must be chosen as fast as possible in order to ensure optimal operating conditions.
基金Supported by the National Natural Science Foundation of China(21006127)the National Basic Research Program of China(2012CB720500)
文摘This paper presents some new dynamic interaction analysis approaches for square or non-square systems and a pairing evaluation method. For square stable systems, an open-loop approach is proposed, which features the tradeoff between the contributions of response time constant and delay time to relative gain. For non-square stable systems, an extension from the proposed open-loop approach for square systems is presented and the corresponding pairing procedure is given. No interaction analysis approach is perfect for all systems, so any recommended pairing needs to be examined. An evaluation method is proposed in closed-loop with optimal controllers for each loop and whether the pairing is appropriate can be evaluated through testing if the equivalent relative gain is within defined scope. The advantages and effectiveness of proposed interaction analysis approaches and pairing evaluation method are highlighted via several examples of industrial processes.
文摘The paper represents very simple procedure of identification, based on step response of the process. Results of identification are extended Strejc＇s models （named ZenanX model, models with n equivalent time constants and delay time）. Described mathematically proved equations which show an easy way of filtering and differentiation step response with the help of the data window. It also supports the contention that the point of intersection of tangent to the integrated step response and the X axis represents the sum of time constants and delay time, and showed the method （named ZenoX method） of determining Strej c extended model. For the determination of the impulse response （important for definition of models） are used orthonormal functions （Laguerre）. Simulations are made in the package Matlab. The paper represents results from numerous simulations. The method allows simple and rapid extraction of the Extended Strejc model （ZenanX model）, which is often used to adjust the controllers. Through the simulations of the procedure of removing noise from measured step response is described.
文摘The relaxation of a one-dimensional magnetic nanoparticle linear chain with lattice constant a is investigated in absence of applied field. There is an equilibrium state （or steady state） where a11 magnetic moments of particles lie along the chain （x-axis）, back to which the magnetic nanoparticle chain at other state will relax. It is found that the relaxation time T= is determined by Tx = 10β×α3. This relaxation is compared with that of single magnetic nanoparticle system.
