A new modeling methodology for ripple dynamics driven by oscillatory flows using a Eulerian two‐phase flow approach is presented in order to bridge the research gap between near‐bed sediment transport via ripple migration and suspended load transport dictated by ripple induced vortices. Reynolds‐averaged Eulerian two‐phase equations for fluid phase and sediment phase are solved in a two‐dimensional vertical domain with a k‐ε closure for flow turbulence and particle stresses closures for short‐lived collision and enduring contact. The model can resolve full profiles of sediment transport without making conventional near‐bed load and suspended load assumptions. The model is validated with an oscillating tunnel experiment of orbital ripple driven by a Stokes second‐order (onshore velocity skewed) oscillatory flow with a good agreement in the flow velocity and sediment concentration. Although the suspended sediment concentration far from the ripple in the dilute region was underpredicted by the present model, the model predicts an onshore ripple migration rate that is in very good agreement with the measured value. Another orbital ripple case driven by symmetric sinusoidal oscillatory flow is also conducted to contrast the effect of velocity skewness. The model is able to capture a net offshore‐directed suspended load transport flux due to the asymmetric primary vortex consistent with laboratory observation. More importantly, the model can resolve the asymmetry of onshore‐directed near‐bed sediment flux associated with more intense boundary layer flow speed‐up during onshore flow cycle and sediment avalanching near the lee ripple flank which force the onshore ripple migration.

中文翻译：

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基于欧拉两相模型的陆上波纹迁移数值研究

提出了一种使用欧拉两相流方法对由振荡流驱动的波纹动力学进行建模的新方法，以弥合近床沉积物通过波纹迁移和波动引起的涡旋所决定的悬浮载荷迁移之间的研究差距。雷诺平均流体相和沉淀物相欧拉两相方程与二维垂直域求解ķ - ε闭合件可防止湍流和颗粒应力，闭合件可防止短时碰撞和持久接触。该模型可以解决沉积物运移的全部剖面，而无需进行常规的近床荷载和悬浮荷载假设。该模型通过斯托克斯二阶（陆上速度偏斜）振荡流驱动的轨道脉动的振荡隧道实验进行了验证，在流速和沉积物浓度方面具有良好的一致性。尽管目前的模型对远离稀薄区域的波纹的悬浮沉积物浓度进行了预测，但是该模型预测的陆上波纹迁移速率与实测值非常吻合。还进行了另一个由对称正弦振荡流驱动的轨道波纹情况，以对比速度偏斜的影响。由于与实验室观察结果一致的不对称初级涡流，该模型能够捕获海上定向悬浮净负荷运输通量。更重要的是，该模型可以解决陆上定向近床沉积物通量的不对称性，这与陆上流动周期中边界层流动速度加快以及在背风波纹侧面附近的沉积物雪崩会迫使陆上波纹迁移有关。