Propagation of flexural-gravity waves

The propagation of flexural-gravity waves in a coupled submerged and floating plate-system is studied, and the complex flexural gravity wave propagation properties are investigated in the frequency and time domain, The system exhibits two modes of propagation analogous to the surface and internal waves in a two-layer fluid. A wave in the interface (red line), induced by the motion in the surface (blue line) can be observed. A part of the wave envelope remains stationary (left figure red line) and can even move in the leftward direction that is opposite to the direction of the wave propagation (right side figure red line). This observations are due to wave blocking in which the wave energy propagation halts and can even generate negative energy flux (responsible for leftward movement).

Currently, I am also working on the wave scattering process by a crack in the elastic structure, a common phenomenon in sea-ice where the theory of hydroelasticity is conveniently applied by researchers when wave blocking occurs. The physical problem is considered both in the homogeneous and stratified water column.

            Apart from that, I have started working on the flood prediction models lately aiming to provide an improved model for the flood-prediction of the Brahmaputra river basin. The Brahmaputra River in India (Assam state) is subject to high variation in flow-rate across the season, abrupt channel configuration change, and huge sediment transport. This contributes to a higher risk of channel overflow, which is evident from the history of flooding in the Brahmaputra basin over the years. Other parameters such as slope, flow from other tributaries of the Brahmaputra River, canopy layers, soil characteristics, average rainfall, etc. act as a catalyst in flooding. Every year, during monsoon, a vast area in the basin gets affected by the overflow of the river and thus puts the lives of thousands of people residing in the fertile alluvial area in danger. My plan is to build a new mathematical model by integrating atmospheric prediction model, groundwater and existing flood prediction system with improved inputs on DEM (Digital Elevation Model) etc. Currently, I am working on Long-Range Prediction and Predictability of Indian Summer Monsoon Rainfall. An accurate prediction on rainfall will allow us to improve the hydrology model, to be taken up at a later stage.

Dr.Santu Das

PUBLICATION:

  1. S. Das*, T. Sahoo & M.H. Meylan, “An investigation of the properties of flexural-gravity wave propagation in a coupled submerged and floating plate system”, European journal of Mechanics B/Fluids, Vol 82 (2020), pp 123 – 134 (IF: 2.131, * Corresponding author)
  2. S.C. Barman, S. Das*, T. Sahoo & M.H. Meylan, “Scattering of flexural-gravity waves by a crack in a floating ice-sheet due to mode conversion during blocking” – revised version to be submitted to Journal of Fluid Mechanics (IF: 3.354,    * Corresponding author)