In this study, shallow water equations (SWEs) in Cartesian coordinates were used to foresee water levels (WLs) on account of the nonlinear tide-surge interaction (TSI) associated with the recent cyclonic storm Roanu that hit the eastern coast of Bangladesh. A fully explicit finite-difference method (FDM) was implemented to solve the SWEs. A one-way nesting approach was implemented for incorporating coastal complexity with the lowest cost. The land-sea interface of every nested scheme was made favorable for employing the FDM via the stair-step technique. To incorporate river dynamics, freshwater Meghna River discharge was taken into consideration in the innermost scheme. An appropriate tidal regime in the domain was established after forcing the sea-level to be oscillatory applying the four effective tidal constituents, viz. M₂ (principal lunar semidiurnal), S₂ (principal solar semidiurnal), K₁ (lunisolar diurnal), and O₁ (principal lunar diurnal) on the southern boundary of the outermost scheme. Numerical experiments were performed by the model to estimate WLs due to tide, surge, and TSI associated with tropical storm Roanu in the coastal areas of Bangladesh. Our estimated WLs due to TSI were in good agreement with the observed data procured from the Bangladesh Inland Water Transport Authority (BIWTA) and some reported results. The model was found to perform well on the basis of the root mean square error (RMSE) values and computational cost.

在这项研究中，由于与最近袭击孟加拉国东部海岸的罗阿努飓风有关的非线性潮汐-潮气相互作用（TSI），使用笛卡尔坐标系中的浅水方程（SWE）来预测水位（WLs）。实现了一种完全显式的有限差分方法（FDM）来解决SWE。实施了一种单向嵌套方法，以最低的成本结合了海岸的复杂性。通过嵌套技术，使每个嵌套方案的陆海界面都有利于采用FDM。为了纳入河流动力学，最内层方案考虑了淡水的梅格纳河流量。应用四种有效的潮汐分量，即迫使海平面振荡后，在域中建立了适当的潮汐机制。在最外层方案的最南边界上，M ₂（主月日），S ₂（主日太阳），K ₁（月日日）和O ₁（主月日）。该模型进行了数值实验，以估算与孟加拉国沿海地区的热带风暴罗阿努有关的潮汐，潮汐和TSI引起的WL。由于TSI，我们估计的WL值与从孟加拉国内陆水运局（BIWTA）获得的观测数据和一些报告的结果非常吻合。发现该模型在均方根误差（RMSE）值和计算成本的基础上表现良好。