搜索

x

考虑对数率风廓线动态修正的海上工程场地风场数值模拟

Numerical simulation of wind field at offshore engineering sites with dynamic correction of logarithmic wind profile

  • 摘要: 在动态波浪环境下,波浪起伏与破碎改变了海气界面状态,而经典对数律风剖面模型假定为海面静止,且未明确摩擦速度与粗糙度长度的确定准则,难以实现海上风场的精确计算。本文依托Charnock模型,搭建了高精度的计算流体力学数值水池开展多工况风浪联合模拟,探究波浪对海上工程场地风场的影响规律,建立了海上对数率平均风速剖面修正模型。结果表明:与实测数据相比,基于Charnock系数的风廓线修正方法精度在88%以上,海面粗糙长度由规范固定值(0.002)扩展为随基准风速动态变化(0.000 23~0.005 89);近水面风速脉动由波浪波动状态主导,波动周期与波浪一致;波浪对风场的扰动仅限于近水面有限高度,当波高不超过4 m时,距水面24 m以上区域波浪影响可完全忽略。

     

    Abstract: In wave conditions, wave motion and breaking change the air-sea interface. However, the classic logarithmic wind profile model assumes a still sea surface, and does not clearly define how to determine friction velocity and roughness length, making it hard to calculate offshore wind fields accurately. Based on the Charnock model, this article develops a high-accuracy CFD numerical wave tank to perform combined wind-wave simulations under multiple conditions. It investigates the effects of waves on wind fields at offshore engineering sites and establishes a corrected logarithmic mean wind profile model for offshore conditions. The results show that: compared with measured data, the wind profile correction method based on the Charnock coefficient has an accuracy of over 88%. The sea surface roughness length is expanded from a fixed standard value (0.002) to a dynamic value that changes with reference wind speed (0.00023 to 0.00589). Near-surface wind speed fluctuations are mainly driven by wave conditions, with the same fluctuation period as the waves. Wave disturbance to the wind field is limited to a certain height near the water surface; when wave height is no more than 4 m, wave effects can be completely ignored in areas more than 24 m above the water surface.

     

/

返回文章
返回