Elucidation of generation and development mechanism of wind-wave in polar region and formulation of its bulk equation

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04699
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Iwate University
• Principal Investigator: Ogasawara Toshinori 岩手大学, 理工学部, 教授 (60374865)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 風波 / 極域 / 気液温度勾配

Outline of Final Research Achievements

This study aims to identify characteristics of wind waves with an air-liquid temperature gradient. The following conclusions were reached in this study.
1) The lower the air temperature relative to the water temperature, the greater the wave height will tend to be. 2) The cause of the more significant wave height is inferred to be the increase in momentum transported from the wind to the water surface due to the decrease in water surface temperature and the increase in the kinematic viscosity of the water surface. 3) When the wind speed increases and the water surface variability develops, the factors that affect momentum transport are the factors that affect the water surface kinematic viscosity and the water surface momentum transport. 3) As wind velocity increases and water surface variability develops, the factor influencing momentum transport changes from the kinematic viscosity of the water surface to waves drag.

Free Research Field

海岸工学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は、気候変動シミュレーションにおいて十分に検討されていない極域における気液境界層のモデル化の基になる貴重なデータを取得することができた。特に、気液温度勾配下における風波の波浪特性を明らかにし、気温の影響を受けた気液双方の動粘性係数の変化が波の発達に大きな影響を及ぼすことを明らかにした。このような事実は、観測データの乏しい極域における風波の発生・発達率の精度を高めることを可能とし、地球規模における気候変動の予測精度の向上に結びつく成果と言える。