This study builds on Huntley and Ryan (2018, https://doi.org/10.1002/2017JC012748) and related prior works on channels and estuaries by considering solutions for the same subtidal dynamics but with alternative integral flow constraints. Prior solutions do not have a truly two‐dimensional (2‐D) flow field, as axial changes in the axial flow are implied. Three constraint types are considered: the Constant case with spatially constant density gradients constrained with section‐integrated flow (as in prior works), Semi‐Variable case with a constant axial density gradient and laterally variable lateral density gradient constrained with depth‐integrated lateral flow, and Variable case with spatially variable density gradients in both directions constrained with depth‐integrated axial and lateral flows. The Semi‐Variable and Variable cases can produce solutions with truly 2‐D flow if the depth‐integrated lateral flow is set to zero everywhere. Differences among solutions are illustrated with idealized and realistic applications from Huntley and Ryan (2018, https://doi.org/10.1002/2017JC012748). For the idealized application, the Constant case and the Semi‐Variable case with 2‐D flow have clear differences in axial velocity and stark contrasts in lateral flow (and density gradients). For the Nares Strait application, the Variable case with observed depth‐averaged axial and lateral velocities is best able to represent the fastest observed down‐channel velocities, the weak reversed flow on one side of the channel, and the observed lateral flow structure. Overall, selecting different integral constraints on flow conspicuously changes the subtidal flow, opens up new possibilities for truly 2‐D flow solutions, and provides additional flexibility for representing observed conditions in realistic situations.

中文翻译：

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不同积分约束下河道和河口的潮汐流解

这项研究基于Huntley和Ryan（2018，https://doi.org/10.1002/2017JC012748）以及有关河道和河口的相关先验工作，通过考虑相同的潮汐动力学解决方案但具有可选的整体流动约束条件。先前的解决方案没有真正的二维（2D）流场，因为这暗示了轴向流的轴向变化。考虑了三种约束类型：空间常量密度梯度受截面积分流约束的“恒定”情况（如先前的工作）；轴向密度梯度恒定且横向变量横向密度梯度受深度综合的横向流约束的“半可变”情况和变量在两个方向上都有空间可变的密度梯度的情况，受深度积分的轴向和横向流动的限制。如果将深度积分的横向流各处都设置为零，则“半变量和可变”情况可以产生真正的二维流解。亨特利（Huntley）和瑞安（Ryan）（2018，https://doi.org/10.1002/2017JC012748）通过理想化和现实的应用说明了解决方案之间的差异。对于理想的应用，具有二维流动的“恒定”情况和“半变量”情况在轴向速度上存在明显差异，并且在横向流动（和密度梯度）方面存在明显的反差。对于Nares Strait应用程序，变量观察到的平均深度的轴向和横向速度的情况最能代表观察到的最快的下行通道速度，通道一侧的弱反向流动以及观察到的横向流结构。总体而言，在流量上选择不同的积分约束会明显改变潮汐流，为真正的二维流量解决方案开辟新的可能性，并为表示实际情况中的观测条件提供了更大的灵活性。