多种大气稳定度下的复杂地形风电场精细化风能模拟

Chinese wind energy resources development in Micro-location Selection of wind farms and refinement evaluation are seriously depending on the abroad"black box" software .system,don't control the core technology.According to the current embarrassing situation,independent development of small-scale numerical model is very urgent.Insufficient for the existing small-scale wind model using the assumption of near-neutral atmospheric stratification,the project will work with fine-scale wind energy model NLMSFD developed of Canada YORKU University and Canada Meteorological Administration.changed near-neutral atmospheric stratification and wind profile assumes which inconsistent with the actual situation.Through observation of wind,temperature and turbulent on field wind tower,we find a variety of atmospheric stability conditions,wind speed vertical profile of expression .and its parameters suitable for underlying surface of the pilot area of complex terrain wind farm.Increase calculation program in the model.Find out a reasonable method to determine the surface roughness and zero plane displacement of wind farm.Increase the amendment of zero-plane displacement in the model of the near surface wind speed Logarithmic rate,correct the assumption of u=0 at Z=z0.Increase the rough sub-layer transition between lower model and surface, then model Theoretical basis closer to the actual situation.Thereby increasing the simulation accuracy, expanding the applicability of fine-scale wind model in non-neutral stratification conditions.

面对中国风能资源开发利用在风电场微观选址和精细化评估中严重依赖国外"黑箱"软件系统不掌握核心技术的尴尬现状而提出自主发展小尺度数值模式的迫切需求。针对现有小尺度风能模式采用近中性大气层结等假设的不足，本项目拟对加拿大YORKU 大学和加拿大国家气象局共同开发的精细尺度风能模式NLMSFD展开工作，改进模式中常与实际情况不符的近中性大气层结及风廓线假设，通过开展野外测风塔上风、温及湍流涡动相关观测，找出适合于试验区风电场复杂地形下垫面的多种大气稳定度条件下的风速垂直廓线表达式及其参数，在模式中增加相应计算方案；找出风电场现场确定地表粗糙度和零平面位移的合理方法，在模式近地层风速对数率中增加零平面位移的修正，改正Z=z0处，u＝0的假设，在模式下层与地表之间增加粗糙次层的过渡，使模式理论基础更接近于实际情况。进而提高其模拟精度，拓展精细尺度风能模式在非中性层结条件下的适用性。

基本按计划完成了项目任务。开展了野外测风塔上风、温及湍流涡动相关观测，对取得的数据进行质量控制。分析了复杂地形下不同稳定度划分方法的适用性。分析了取得的测风塔风速廓线，在研究中发现在某些复杂地形下，近地层风速廓线对数率或指数率的适用性有一定问题。在这种情形下，地表粗糙度的拟合也有所变化。虽已经有些思路和初步结果，但还需进一步的验证和论证，能够立即发表或公布的比较完善的成果还需等待。表明在复杂地形下，近地层风速廓线的适用性或表现形式值得进一步研究。精细化风能模式NLMSFD对地表粗糙度和摩擦速度比较敏感，地表粗糙度的取值可改变扰动风速廓线形状，对模式模拟精度影响较大，扰动风速数值大多随其增大而增大，极大值出现高度随其增大而增高。模式驱动风速改变几乎不改变扰动风速廓线形状，扰动风速数值随其增大而增大。地形导致的风速变化对近地面层影响最大。如何合理地确定地表粗糙度，对MSFD模式的成功应用有较大影响。该模式在较陡峭地形下，有较大偏差，通过调整驱动参数及数据可改善模拟结果。对于非中性条件下的风速廓线模拟还有改进空间，提高其风能模拟精度。