In this paper, we establish several inequalities for the the generalized linear distortion function λ（a, K） by using the monotonicity and convexity of certain combinations λ（a, K）.
The scaled-model thickness cannot be reduced by the same scaling factor as the length in similitude analysis of the space solar power station(SSPS)large-scale concentrator unit,resulting one-dimensional linear distort...The scaled-model thickness cannot be reduced by the same scaling factor as the length in similitude analysis of the space solar power station(SSPS)large-scale concentrator unit,resulting one-dimensional linear distortion.Thus,the complete scaling law is invalid,established by the traditional similitude analysis,reducing the prediction accuracy.To weaken the distortion effect,a chain separate similitude analysis method is presented to establish the distortion scaling law,thereby enhancing the prediction accuracy.First,a global scaling law is obtained based on dimensional analysis.Second,distortion model is formed by introduced a distortion coefficient,which allows for the global scaling law to be chain-separated into complete and partial similitude scales.Third,two sub-models of complete similitude and partial similitude are constructed respectively to weaken the distortion effect.Then,the scaling laws are established including complete and partial similitude,respectively.On this basis,the natural frequency distortion scaling law is derived.Finally,finite element models of the concentrator unit prototype and distortion model are developed to validate the suggested method.Through simulation analysis,the large-scale prototype first-order natural frequency predicted value is 28.34 Hz,while the theoretical value is 28.32 Hz.The prediction error of the first four orders’natural frequency for the prototype is kept within 0.4%.Results indicate the proposed method can improve the accuracy by one order of magnitude compared to the existing methods,greatly weaken the distortion effect,and effectively solve the one-dimensional linear distortion problem.展开更多
Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the linear stability beh...Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the linear stability behaviour of parallel shear flow, presents unstable results of plane Couette flow and pipe Poiseuille flow to two-dimensional or axisymmetric disturbances for the first time, and obtains neutral curves of these two motions under certain definition.展开更多
基金Supported by the National Natural Science Foundation of China(11071069, 11171307)the Natural Science Foundation of Hunan Province(09JJ6003)
文摘In this paper, we establish several inequalities for the the generalized linear distortion function λ（a, K） by using the monotonicity and convexity of certain combinations λ（a, K）.
基金supported by the Civil Aerospace Technology Research Project(No.D010103)National Key R&D Program of China(No.2021YFB3900300).
文摘The scaled-model thickness cannot be reduced by the same scaling factor as the length in similitude analysis of the space solar power station(SSPS)large-scale concentrator unit,resulting one-dimensional linear distortion.Thus,the complete scaling law is invalid,established by the traditional similitude analysis,reducing the prediction accuracy.To weaken the distortion effect,a chain separate similitude analysis method is presented to establish the distortion scaling law,thereby enhancing the prediction accuracy.First,a global scaling law is obtained based on dimensional analysis.Second,distortion model is formed by introduced a distortion coefficient,which allows for the global scaling law to be chain-separated into complete and partial similitude scales.Third,two sub-models of complete similitude and partial similitude are constructed respectively to weaken the distortion effect.Then,the scaling laws are established including complete and partial similitude,respectively.On this basis,the natural frequency distortion scaling law is derived.Finally,finite element models of the concentrator unit prototype and distortion model are developed to validate the suggested method.Through simulation analysis,the large-scale prototype first-order natural frequency predicted value is 28.34 Hz,while the theoretical value is 28.32 Hz.The prediction error of the first four orders’natural frequency for the prototype is kept within 0.4%.Results indicate the proposed method can improve the accuracy by one order of magnitude compared to the existing methods,greatly weaken the distortion effect,and effectively solve the one-dimensional linear distortion problem.
文摘Based on the hydrodynamic stability theory of distorted laminar flow and the kind of distortion profiles on the mean velocity in parallel shear flow given in paper [1], this paper investigates the linear stability behaviour of parallel shear flow, presents unstable results of plane Couette flow and pipe Poiseuille flow to two-dimensional or axisymmetric disturbances for the first time, and obtains neutral curves of these two motions under certain definition.
