The collision of two opposing, horizontal gravity currents is investigated numerically using Large Eddy Simulation (LES). The classical lock-exchange configuration is considered for symmetric collision (currents with same densities and heights). A partial-depth setup is used which is considered to simulate better the collision in deep air column of atmosphere. LES results are validated using available experimental and DNS data (Fragoso et al. in J Fluid Mech 734:1–10, https://doi.org/10.1017/jfm.2013.475; Frantz et al. in Comput Fluids, 2021. https://doi.org/10.1016/j.compfluid.2021.104902) for the classical full depth lock-exchange gravity current. Numerical experiments are performed considering the effects of D/H (D is the height of dense fluid in the lock, H is the tank height) and Grashof number (Gr) on the collision characteristics. The former varies from 0.25 to 1.0 and the latter from \(10^6\) to \(10^{12}\). Maximum vertical displacement and maximum vertical velocity increase with decreasing D/H from 1.0 up to 0.5. They remain constant for \(D/H \le 0.5\). Maximum vertical displacement decreases with Gr number opposite to the corresponding variation of the maximum equivalent height. Maximum vertical velocity decreases with increasing Gr number, due to increased turbulence. For \(Gr \ge 5 \times 10^8\) (a) the maximum vertical displacement is almost constant (equal to 1.4D), (b) the temporal evolution of energies is approximately the same. At the time of maximum height the maximum potential energy and the minimum kinetic energy are approximately \(80\%\) and \(15\%\) of the initial potential energy, respectively, and (c) a region with intense turbulence and mixing of less dense fluid (\(C\le 0.6\), C is the concentration) is formed after the occurrence of maximum height in the middle of the domain.

使用大涡模拟 (LES) 对两个相对的水平重力流的碰撞进行了数值研究。经典的锁交换配置被考虑用于对称碰撞（具有相同密度和高度的电流）。使用了部分深度设置，被认为可以更好地模拟大气深层气柱中的碰撞。LES 结果使用可用的实验和 DNS 数据进行验证（Fragoso 等人在 J Fluid Mech 734:1-10, https://doi.org/10.1017/jfm.2013.475；Frantz 等人在 Comput Fluids, 2021. https ://doi.org/10.1016/j.compfluid.2021.104902) 用于经典的全深度锁定交换重力流。考虑到D / H ( D是锁中稠密流体的高度，H是罐体高度）和格拉肖夫数（Gr）对碰撞特性的影响。前者从 0.25 到 1.0 不等，后者从\(10^6\)到\(10^{12}\)。最大垂直位移和最大垂直速度随着D / H从 1.0 减小到 0.5 而增加。它们对于\(D/H \le 0.5\)保持不变。与最大等效高度的相应变化相反，最大垂直位移随着Gr数的减少而减小。由于湍流增加，最大垂直速度随着Gr数的增加而降低。为了\(Gr \ge 5 \times 10^8\) (a) 最大垂直位移几乎是恒定的（等于 1.4 D），(b) 能量的时间演化大致相同。在最大高度时，最大势能和最小动能分别约为初始势能的\（80\%\）和\（15\%\），并且（c）具有强烈湍流和在域中间出现最大高度后形成密度较小的流体（\（C\le 0.6\），C是浓度）的混合。