By the use of the 3/2 power law presented by Toba combined with the significant wave energy balance equation for wind wave, wind wave growth at a limited fetch is analytically investigated. The new wind wave growth re...By the use of the 3/2 power law presented by Toba combined with the significant wave energy balance equation for wind wave, wind wave growth at a limited fetch is analytically investigated. The new wind wave growth relations (WWGRs) are analytically derived with sheltering coefficient and wind drag coefficient as parameters. The geometrical average of observational values of sheltering coefficient and the arithmetic average of observational values of wind drag coefficient are applied to determine the new WWGRs. Comparisons with existing empirical WWGRs are made.展开更多
A recent formula for the lift force on a low speed wing of circular arc cross-section [<span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style=&quo...A recent formula for the lift force on a low speed wing of circular arc cross-section [<span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;"><a href="#ref1">1</a></span></b></span></span><span><span></span></span><span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">] is adapted to the upward pressure force on the crests of a surface gravity wave propagating in the wind. In both cases</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the main feature is the utilization of the air’s compressibility. At and near a wave crest</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> it is predicted that the air density is increased over the ambient value and that the air density decreases inversely as the square of the upward distance from the radius of curvature of the crest. As a consequence</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the air pressure also decreases upward inversely as the square of the same distance. Therefore, an upward pressure force on each crest occurs which presumably will make the crests grow. Growth rates are largest for small </span><span style="font-family:Verdana;">wavelengths and large mean slopes of the wave surface. Contrary winds should produce </span><span style="font-family:Verdana;">wave growth (not damping) as well as no wind at all.</span></span></span></span>展开更多
Combining the 3/2 power law proposed by Toba with the significant wave energy balance equation for wind waves, wave growth in deep water for short fetch is investigated. It is found that the variations of wave height ...Combining the 3/2 power law proposed by Toba with the significant wave energy balance equation for wind waves, wave growth in deep water for short fetch is investigated. It is found that the variations of wave height and period with fetch have the form of power function with fractional exponents 3/8 and 1/4 respectively. Using these exponents in the power functions and through data fitting, the concise wind wave growth relations for short fetch are obtained.展开更多
In the present paper combining the relationship between wave steepness andwave age with the significant wave energy balance equation for wind wave, a new wind wave growthrelation is presented. Comparisons with the oth...In the present paper combining the relationship between wave steepness andwave age with the significant wave energy balance equation for wind wave, a new wind wave growthrelation is presented. Comparisons with the other existing wind wave growth relations show that theresults in present paper accord better with the wind wave growth process.展开更多
Based on the dynamic essence of air-sea interactions, a feedback type of spatial evolu-tion equation is suggested to match reasonably the growing process of wind waves. This simple equation involving the dominant fact...Based on the dynamic essence of air-sea interactions, a feedback type of spatial evolu-tion equation is suggested to match reasonably the growing process of wind waves. This simple equation involving the dominant factors of wind wave growth is able to explain the transfer of en-ergy from high to low frequencies without introducing the concept of nonlinear wave-wave interac-tions, and the results agree well with observations. The rate of wave height growth derived in this dissertation is applicable to both laboratory and open sea, which solidifies the physical basis of using laboratory experiments to investigate the generation of wind waves. Thus the proposed spa-tial evolution equation provides a new approach for the research on dynamic mechanism of air-sea interactions and wind wave prediction.展开更多
Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dis...Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dissipation parameterizations proposed by Tsikunov, Hasselmann, and Phillips are also analyzed. Likewise it is found by analogy that the similarity of integrals of the three dissipation parameterizations exists. The similarities of wind input and dissipation are applied to the investigation of the fetch-limited growth of wind waves, together with the 3/2 power law presented by Toba. Some semi-empirical formulas concerning the growth of wave height and period with fetch are presented. The results from the formulas are in good agreement with previous field observations.展开更多
The spatial growth of turbulent wind waves is investigated theoretically and experimentally. Introduction of wave induced turbulent Reynolds stress, in particu- lar at the average interface, makes great improvement in...The spatial growth of turbulent wind waves is investigated theoretically and experimentally. Introduction of wave induced turbulent Reynolds stress, in particu- lar at the average interface, makes great improvement in the prediction of wind wave properties.展开更多
基金by the major state basic research program(No.G1999043809)the National Natural Science Foundation of China(No.40076003)the the Excellent Young Teachers Program of Ministry of Education,P.R.China(M.[2001]39)
文摘By the use of the 3/2 power law presented by Toba combined with the significant wave energy balance equation for wind wave, wind wave growth at a limited fetch is analytically investigated. The new wind wave growth relations (WWGRs) are analytically derived with sheltering coefficient and wind drag coefficient as parameters. The geometrical average of observational values of sheltering coefficient and the arithmetic average of observational values of wind drag coefficient are applied to determine the new WWGRs. Comparisons with existing empirical WWGRs are made.
文摘A recent formula for the lift force on a low speed wing of circular arc cross-section [<span style="font-family:Verdana;"><span style="font-family:Verdana;"><b><span style="font-family:Verdana;"><a href="#ref1">1</a></span></b></span></span><span><span></span></span><span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">] is adapted to the upward pressure force on the crests of a surface gravity wave propagating in the wind. In both cases</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the main feature is the utilization of the air’s compressibility. At and near a wave crest</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> it is predicted that the air density is increased over the ambient value and that the air density decreases inversely as the square of the upward distance from the radius of curvature of the crest. As a consequence</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the air pressure also decreases upward inversely as the square of the same distance. Therefore, an upward pressure force on each crest occurs which presumably will make the crests grow. Growth rates are largest for small </span><span style="font-family:Verdana;">wavelengths and large mean slopes of the wave surface. Contrary winds should produce </span><span style="font-family:Verdana;">wave growth (not damping) as well as no wind at all.</span></span></span></span>
基金supports from the Major State Basic Research Program(No.G1999043809)the National Natural Science Foundation(No.40076003)+1 种基金the EYTP of MOE(No.200139)support by Visiting Scholar Foundation of Key Lab.in the University.
文摘Combining the 3/2 power law proposed by Toba with the significant wave energy balance equation for wind waves, wave growth in deep water for short fetch is investigated. It is found that the variations of wave height and period with fetch have the form of power function with fractional exponents 3/8 and 1/4 respectively. Using these exponents in the power functions and through data fitting, the concise wind wave growth relations for short fetch are obtained.
文摘In the present paper combining the relationship between wave steepness andwave age with the significant wave energy balance equation for wind wave, a new wind wave growthrelation is presented. Comparisons with the other existing wind wave growth relations show that theresults in present paper accord better with the wind wave growth process.
基金the National Natural Science Foundation of China (Grant No. 49976003)
文摘Based on the dynamic essence of air-sea interactions, a feedback type of spatial evolu-tion equation is suggested to match reasonably the growing process of wind waves. This simple equation involving the dominant factors of wind wave growth is able to explain the transfer of en-ergy from high to low frequencies without introducing the concept of nonlinear wave-wave interac-tions, and the results agree well with observations. The rate of wave height growth derived in this dissertation is applicable to both laboratory and open sea, which solidifies the physical basis of using laboratory experiments to investigate the generation of wind waves. Thus the proposed spa-tial evolution equation provides a new approach for the research on dynamic mechanism of air-sea interactions and wind wave prediction.
基金Supported by the High-Tech Research and Development Program of China (863 Program, No. 2001AA633070 2003AA604040)the National Natural Science Foundation of China (No. 40476015).
文摘Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dissipation parameterizations proposed by Tsikunov, Hasselmann, and Phillips are also analyzed. Likewise it is found by analogy that the similarity of integrals of the three dissipation parameterizations exists. The similarities of wind input and dissipation are applied to the investigation of the fetch-limited growth of wind waves, together with the 3/2 power law presented by Toba. Some semi-empirical formulas concerning the growth of wave height and period with fetch are presented. The results from the formulas are in good agreement with previous field observations.
文摘The spatial growth of turbulent wind waves is investigated theoretically and experimentally. Introduction of wave induced turbulent Reynolds stress, in particu- lar at the average interface, makes great improvement in the prediction of wind wave properties.