We propose a novel fast numerical calculation method for the Rayleigh-Sommerfeld diffraction integral,which is developed based on the existing scaled convolution method.This approach enables fast cal-culations for gen...We propose a novel fast numerical calculation method for the Rayleigh-Sommerfeld diffraction integral,which is developed based on the existing scaled convolution method.This approach enables fast cal-culations for general cases of off-axis scenarios where the sampling intervals and numbers of the input and observation planes are unequal.Additionally,it allows for arbitrary adjustment of the sampling interval of the impulse response function,facilitating a manual trade-off between computational load and accuracy.The er-rors associated with this method,which is equivalent to interpolation,primarily arise from the discontinuities of the sampling matrix of the impulse response function on its boundaries of periodic extension.To address this issue,we propose the concept of the padding function and its construction method,and evaluate its ef-fectiveness in enhancing computational accuracy.The feasibility of the proposed method is verified by nu-merical simulation and compared with the direct integration DI-method in a simplified scenario.It shows that the proposed method has good computational accuracy for the general case where the sampling interval of the input and observation plane is not equal under non-near-field diffraction,and when the diffraction distance is large,although the computational accuracy of the proposed method cannot exceed that of the DI-method,the computational amount can be significantly reduced with almost no effect on the computational accuracy.This method provides a general numerical calculation scheme of diffraction in the non-near field case for areas such as computational holography.展开更多
针对可再生能源高比例渗透下多区域综合能源互联系统(Multi-region integrated energy interconnection system,MRIEIS)所面临的消纳与经济性挑战,构建了一个包含电、氢、热、冷多能流的多时间尺度优化调度模型。该模型以系统日总运行...针对可再生能源高比例渗透下多区域综合能源互联系统(Multi-region integrated energy interconnection system,MRIEIS)所面临的消纳与经济性挑战,构建了一个包含电、氢、热、冷多能流的多时间尺度优化调度模型。该模型以系统日总运行成本最低为目标,建立动态多能流枢纽深度集成了电转氢(Power to hydrogen,P2H)、储氢罐、氢气管网以及燃气轮机(GT)掺氢等动态调度关键技术。通过日前、日内、实时三阶段滚动优化对系统进行精细化调度。算例分析基于一个包含居民、工业和混合型区域的典型场景,结果表明,该模型能够有效实现系统经济性与环保性的统一,总运行成本控制在56.48万元,同时系统总可再生能源利用率高达98.53%。氢能作为灵活的能量载体,其时空价值得到了充分发挥。掺氢策略有效刺激了氢能消耗,形成了“制-储-输-用”的闭环,为构建以新能源为主体的新型电力系统提供了可行的技术路径和调度策略参考。展开更多
The pantograph cavity coupling system(PCCS)of high-speed trains,as a representative region for aerodynamic noise generation,merits further investigation into its scale effects.In this paper,the large-eddy simulation(L...The pantograph cavity coupling system(PCCS)of high-speed trains,as a representative region for aerodynamic noise generation,merits further investigation into its scale effects.In this paper,the large-eddy simulation(LES)and the Ffowcs Williams-Hawkings(FW-H)integral equation are used to calculate and analyze the sound energy intensity distribution pattern and spectral characteristics of the PCCS at different scales(1/1,1/2,1/4,1/8,1/16,1/25,1/50).The research shows that as the scaled model decreases,the relative area of the pantograph submerged by the vehicle boundary layer increases,and its inflow velocity decreases,thereby reducing the overall radiated sound pressure level in this area.For the segments 1/1-1/2 and 1/4-1/16,the dominant scale of sound generation is typical pure tone noise,with distinct similar features in the spectral discrete scales.For the segments 1/25-1/50,the turbulent fluctuation characteristics of the vehicle boundary layer mask the peak features,and the spectrum is dominated by broadband characteristics.Combining the PCCS sound source energy scale correction model and the dimensionless spectrum correction function,a scale correction model for the sound power spectrum of the sound source is obtained,so that the noise results of the reduced-scale model can be corresponded to the full-scale model.This work advances the comprehension of high-speed train aerodynamic noise generation mechanisms and offers critical references for developing precision noise control technologies.展开更多
文摘We propose a novel fast numerical calculation method for the Rayleigh-Sommerfeld diffraction integral,which is developed based on the existing scaled convolution method.This approach enables fast cal-culations for general cases of off-axis scenarios where the sampling intervals and numbers of the input and observation planes are unequal.Additionally,it allows for arbitrary adjustment of the sampling interval of the impulse response function,facilitating a manual trade-off between computational load and accuracy.The er-rors associated with this method,which is equivalent to interpolation,primarily arise from the discontinuities of the sampling matrix of the impulse response function on its boundaries of periodic extension.To address this issue,we propose the concept of the padding function and its construction method,and evaluate its ef-fectiveness in enhancing computational accuracy.The feasibility of the proposed method is verified by nu-merical simulation and compared with the direct integration DI-method in a simplified scenario.It shows that the proposed method has good computational accuracy for the general case where the sampling interval of the input and observation plane is not equal under non-near-field diffraction,and when the diffraction distance is large,although the computational accuracy of the proposed method cannot exceed that of the DI-method,the computational amount can be significantly reduced with almost no effect on the computational accuracy.This method provides a general numerical calculation scheme of diffraction in the non-near field case for areas such as computational holography.
文摘针对可再生能源高比例渗透下多区域综合能源互联系统(Multi-region integrated energy interconnection system,MRIEIS)所面临的消纳与经济性挑战,构建了一个包含电、氢、热、冷多能流的多时间尺度优化调度模型。该模型以系统日总运行成本最低为目标,建立动态多能流枢纽深度集成了电转氢(Power to hydrogen,P2H)、储氢罐、氢气管网以及燃气轮机(GT)掺氢等动态调度关键技术。通过日前、日内、实时三阶段滚动优化对系统进行精细化调度。算例分析基于一个包含居民、工业和混合型区域的典型场景,结果表明,该模型能够有效实现系统经济性与环保性的统一,总运行成本控制在56.48万元,同时系统总可再生能源利用率高达98.53%。氢能作为灵活的能量载体,其时空价值得到了充分发挥。掺氢策略有效刺激了氢能消耗,形成了“制-储-输-用”的闭环,为构建以新能源为主体的新型电力系统提供了可行的技术路径和调度策略参考。
基金Project(52272363)supported by the National Natural Science Foundation of ChinaProject(2025JJ50308)supported by the Natural Science Foundation of Hunan Province,China+2 种基金Project(K-BBY1)supported by the Smart Railway Technology and Application,ChinaProject(1-W32Z)supported by the Postdoc Matching Fund Scheme,ChinaProject(ANCL20200302)supported by the Key Laboratory of Aerodynamic Noise Control,China。
文摘The pantograph cavity coupling system(PCCS)of high-speed trains,as a representative region for aerodynamic noise generation,merits further investigation into its scale effects.In this paper,the large-eddy simulation(LES)and the Ffowcs Williams-Hawkings(FW-H)integral equation are used to calculate and analyze the sound energy intensity distribution pattern and spectral characteristics of the PCCS at different scales(1/1,1/2,1/4,1/8,1/16,1/25,1/50).The research shows that as the scaled model decreases,the relative area of the pantograph submerged by the vehicle boundary layer increases,and its inflow velocity decreases,thereby reducing the overall radiated sound pressure level in this area.For the segments 1/1-1/2 and 1/4-1/16,the dominant scale of sound generation is typical pure tone noise,with distinct similar features in the spectral discrete scales.For the segments 1/25-1/50,the turbulent fluctuation characteristics of the vehicle boundary layer mask the peak features,and the spectrum is dominated by broadband characteristics.Combining the PCCS sound source energy scale correction model and the dimensionless spectrum correction function,a scale correction model for the sound power spectrum of the sound source is obtained,so that the noise results of the reduced-scale model can be corresponded to the full-scale model.This work advances the comprehension of high-speed train aerodynamic noise generation mechanisms and offers critical references for developing precision noise control technologies.
