Author(s): S. Rohini; Sannasiraj S. A; V. Sundar

Linked Author(s):

Keywords: Hydrodynamics; Tides; Currents; Extreme events; Cyclone

Abstract: NUMERICAL MODELLING OF STORM SURGE FOR YAAS CYCLONE IN BAY OF BENGAL ROHINI. S, SANNASIRAJ. S.A, and SUNDAR. V Email: rohinicivil91@gmail.com Past decade has witnessed an increase in the frequency and intensity of cyclones in the Bay of Bengal region which has been posing serious threat. Such severe cyclones with its landfall over the east coast of India has resulted in loss of lives, affected the livelihood of the coastal community and infrastructure. Although, the impact due to these extreme events is just over a few hours or days, its impact along certain stretches have experienced to be equivalent to that due to long term coastal hazards. Thus, the study on the impact of the cyclones over the East Coast of India and prediction of the resulting surge heights are vital in the design the coastal protection measures and other coastal infrastructures. Research findings have highlighted the importance of the hydrodynamic modeling to evaluate the storm surges in a region with poor observational coverage. It has become a pre-requisite to investigate the hydrodynamic response based on the prevailing environmental conditions in order to obtain the design parameters. The hydrodynamic model TELEMAC-2D has been used to simulate the extreme events. In the present study, the characteristics of the storm surge from deeper water to the continental shelf, and over the coastal waters, has been investigated. The TELEMAC-2D is a depth averaged flow module which solves the Saint Venant equation using Finite Element Method (FEM). A high-resolution computational grid was generated with an average mesh size of 200-20000m. The model was driven by tidal forcing along the ocean boundary and discharge at the upstream. The tidal boundary was forced with astronomical tides extracted from TPXO database. The spatial distribution of currents and water surface elevation was obtained from the numerical simulation. The model has been calibrated and validated with the field data measured within the study domain. Comprehensive agreement was found between model results and observed data. The model was also simulated with tide in the presence of wind stress. This was done to understand the influence of wind stress on the flow field and also to calibrate the surface friction parameter. The hydrodynamic simulations with this calibrated model set up, was then performed for the cyclonic event for the computation of the storm surge. A surge analysis due to cyclone Yaas is performed and the results are discussed in this paper

DOI: https://doi.org/10.3850/IAHR-39WC252171192022773

Year: 2022