This paper presents new laboratory-scale numerical simulations of density-driven exchange flows generated across an idealised, submerged sill obstruction under both non-rotating and rotating frames of reference using the Bergen Ocean Model (BOM), a three-dimensional general ocean circulation model. Initial non-rotating BOM simulations are compared directly with previous laboratory data obtained in a large-scale channel facility incorporating an idealised trapezoidal sill. These laboratory experiments demonstrate that the saline intrusion flux across the sill is initially reduced and then eventually fully blocked under increasing net-barotropic flow conditions imposed in the counterflowing upper freshwater layer, with the saline blockage also more evident for reduced sill submergence depths. These parametric dependences are also demonstrated in the equivalent BOM simulations of the non-rotating sill exchange flows, although the numerical model results tend to overpredict both the interfacial velocity and density gradients across the sill (as indicative of suppressed interfacial mixing), as well as the fresh-saline source flux ratio at which full blockage of the saline intrusion occurs. The BOM simulations are then extended to consider rotating sill exchange flow dynamics. In particular, these additional runs demonstrate that Coriolis forces increase the overall blockage of the saline intrusion layer compared to equivalent non-rotating exchange flows, especially when the Rossby number associated with the saline intrusion flow across the sill is considerably less than unity. This effect is largely attributed to the development of Ekman boundary layer dynamics and associated secondary circulations within the bi-directional exchange flows. These are shown to impose strong control on the transverse distribution and extent of the lower saline intrusion flow across the sill and, hence, the parametric conditions under which full saline intrusion blockage is achieved in rotating sill exchange flows.

本文介绍了利用三维普通海洋环流模型Bergen海洋模型（BOM），在非旋转和旋转参照系下，通过理想化，淹没式窗台障碍物产生的密度驱动交换流的新实验室规模数值模拟。 。最初的非旋转BOM模拟直接与以前在具有理想梯形窗台的大型通道设施中获得的实验室数据进行比较。这些实验室实验表明，在增加的逆压上部淡水层中增加的净正压流动条件下，穿过门槛的盐水入侵通量最初会减小，然后最终被完全阻塞，而盐水阻塞对于降低门槛浸没深度也更为明显。尽管数值模型结果倾向于过高地预测跨梁的界面速度和密度梯度（作为抑制界面混合的指示），但非旋转窗台交换流的等效BOM模拟也证明了这些参数依赖性。新鲜盐水源通量比，发生盐水入侵时完全被堵塞。然后将BOM模拟扩展为考虑旋转门槛交换流动力学。特别地，这些额外的运行证明，与等效的非旋转交换流相比，科里奥利力增加了盐水侵入层的总体阻塞，尤其是当与穿过门槛的盐水侵入流相关的Rossby数显着小于1时。这种影响很大程度上归因于埃克曼边界层动力学的发展以及双向交换流中相关的次级循环。这些都显示出对穿过下部门槛的下部盐水侵入流的横向分布和程度以及因此在旋转门槛交换流中实现完全盐水侵入阻塞的参数条件施加了严格控制。