Abstract This article focuses on experimental investigation of the interaction between downburst (DB) and near-surface atmospheric boundary layer (ABL) winds. The flow field of DB immersed into ABL winds (DBABL) is compared against the outflow produced by an isolated DB without ABL winds. The diameter of investigated downdrafts was 3.2 ​m. The study demonstrates that there is a profound difference between the radial velocity components in the DBABL and DB outflows in terms of peak and mean velocities, vertical profile of radial velocity, as well as the overall temporal signature of the velocity records. The asymmetry of the DBABL outflow in the along-ABL wind direction is similar to that observed in real traveling downbursts. The turbulence intensity in the near-surface DBABL winds can exceed 40% in some parts of the outflow where the downburst propagates against ABL winds. The DBABL wind profile is characterized by smaller nose-shape curvature than the DB winds in the part of the outflow where downburst and ABL winds have the same direction. The steady-state ABL wind segments and transient downburst segments in the DBABL velocity records are similar to anemometer records of real downbursts. The paper also shows that the velocity addition DBABL → ≠ DB → + ABL → throughout the outflow.

中文翻译：

---

近地表大气边界层风与下击暴流外流相互作用的实验研究

摘要 本文重点研究下击暴流 (DB) 和近地表大气边界层 (ABL) 风之间相互作用的实验研究。将浸入 ABL 风 (DBABL) 中的 DB 的流场与没有 ABL 风的孤立 DB 产生的流出进行比较。研究的下沉气流的直径为 3.2 米。该研究表明，在峰值和平均速度、径向速度的垂直剖面以及速度记录的整体时间特征方面，DBABL 和 DB 流出中的径向速度分量之间存在显着差异。DBABL 出流沿 ABL 风向的不对称性与实际行进下暴流中观察到的相似。在下击暴流逆着 ABL 风传播的某些流出部分，近地表 DBABL 风的湍流强度可能超过 40%。DBABL 风廓线的特点是在下击暴流和 ABL 风具有相同方向的流出部分中，鼻形曲率比 DB 风小。DBABL 速度记录中的稳态 ABL 风段和瞬态下击暴流段与真实下击暴流的风速计记录相似。论文还表明，在整个流出过程中速度相加 DBABL → ≠ DB → + ABL →。DBABL 速度记录中的稳态 ABL 风段和瞬态下击暴流段与真实下击暴流的风速计记录相似。论文还表明，在整个流出过程中速度相加 DBABL → ≠ DB → + ABL →。DBABL 速度记录中的稳态 ABL 风段和瞬态下击暴流段与真实下击暴流的风速计记录相似。论文还表明，在整个流出过程中速度相加 DBABL → ≠ DB → + ABL →。