סמינר מחלקתי של קרישנו קומר- גלי רוח צעירים בנוכחות זרם

Monday February 24th 2025 at 14:00 

Wolfson Building of Mechanical Engineering, Room 206

Abstract:

The excitation mechanism of wind waves has been a topic of interest for more than a century; numerous experimental studies complemented by theoretical investigations have been conducted to understand this complex phenomenon. However, various aspects of this process remain unclear. The generation and evolution of wind waves are also affected by parameters such as direction and magnitude of wind, bathymetry, salinity, water current, etc. In the open ocean, wind waves often interact with currents driven by wind, tides, strong oceanic currents, etc., as well as with currents in confined environments such as in harbor entrances, river mouths, and lakes.

While the effect of uniform current on deep-water gravity waves has been extensively studied in both field and laboratory settings, however, only limited information is currently available on the diverse facets of the excitation of waves by wind that blows over flowing water. The present study aims to bridge that gap by providing a comprehensive set of experimental data under controlled laboratory setting in the absence and presence of current.

The experiments are carried out in the fully automated wind-wave flume for a wide range of wind and water velocities. The current is generated in both along-wind and counter -wind direction. Surface elevation and other wave parameters along the fetch are measured using both conventional analog and optical sensors. The turbulent velocity profile in air over random, three-dimensional moving water surface is measured using Pitot tube, while water velocity is measured using particle image velocimetry (PIV); and velocity at the air-water interface is determined using particle tracking velocimetry (PTV). The accumulated results are discussed in the framework of viscous shear flow instability theory.

Bio:

Krishanu Kumar earned his B. Tech from the School of Mechanical Engineering at SRM IST, India. In 2020, he joined the research group of Prof. Shemer as a MSc student, during which he collaborated with Prof. Barnea on studying interfacial waves in a confined environment. In 2021, he transferred to a direct PhD track under the supervision of Prof. Shemer. His research focuses on the excitation, interaction, and evolution of non-linear random wind waves in the presence of mean current.