The traditional lumped parameter model of fluid pipe is introduced and itsdrawbacks are pointed out. Furthermore, two suggestions are put forward to remove these drawbacks.Firstly, the structure of equivalent circuit ...The traditional lumped parameter model of fluid pipe is introduced and itsdrawbacks are pointed out. Furthermore, two suggestions are put forward to remove these drawbacks.Firstly, the structure of equivalent circuit is modified, and then the evaluation of equivalentfluid resistance is change to take the frequency-dependent function into account. Both simulationand experiment prove that this model is precise to characterize the dynamic behaviors of fluid inpipe.展开更多
以北京副中心北运河生态带、城北、河西和两河片区为研究区,选取典型强降水过程,基于新一代中尺度天气研究和预报模式(weather research and forecasting model,WRF),通过对物理参数化方案的优选,构建适用于北京副中心的数值天气模型。...以北京副中心北运河生态带、城北、河西和两河片区为研究区,选取典型强降水过程,基于新一代中尺度天气研究和预报模式(weather research and forecasting model,WRF),通过对物理参数化方案的优选,构建适用于北京副中心的数值天气模型。通过区域大气模式可以实现定量降水模拟与预报,为缺乏降水资料地区的相关研究提供数据支撑。研究结果表明:不同参数化方案的模拟结果差异较大,积云参数化方案对研究区强降水模拟效果的影响最大;当云微物理过程取WRF Single-Moment 5-class方案,积云对流过程取Grell-Freitas方案,行星边界层过程取Yonsei University方案,长、短波辐射过程取newer version of the Rapid Radiative Transfer Model方案,表层取Revised MM5 Monin-Obukhov方案,陆地表面取Noah land surface model方案,城市表面取Urban canopy model方案时,模拟结果最优。展开更多
基金This project is supported by National Natural Science Foundation of China (No.59875076).
文摘The traditional lumped parameter model of fluid pipe is introduced and itsdrawbacks are pointed out. Furthermore, two suggestions are put forward to remove these drawbacks.Firstly, the structure of equivalent circuit is modified, and then the evaluation of equivalentfluid resistance is change to take the frequency-dependent function into account. Both simulationand experiment prove that this model is precise to characterize the dynamic behaviors of fluid inpipe.
文摘以北京副中心北运河生态带、城北、河西和两河片区为研究区,选取典型强降水过程,基于新一代中尺度天气研究和预报模式(weather research and forecasting model,WRF),通过对物理参数化方案的优选,构建适用于北京副中心的数值天气模型。通过区域大气模式可以实现定量降水模拟与预报,为缺乏降水资料地区的相关研究提供数据支撑。研究结果表明:不同参数化方案的模拟结果差异较大,积云参数化方案对研究区强降水模拟效果的影响最大;当云微物理过程取WRF Single-Moment 5-class方案,积云对流过程取Grell-Freitas方案,行星边界层过程取Yonsei University方案,长、短波辐射过程取newer version of the Rapid Radiative Transfer Model方案,表层取Revised MM5 Monin-Obukhov方案,陆地表面取Noah land surface model方案,城市表面取Urban canopy model方案时,模拟结果最优。