The shallow-water temperature profile is typically parameterized using a few empirical orthogonal function(EOF)coefficients.However,when the experimental area is poorly known or highly variable,the adaptability of the...The shallow-water temperature profile is typically parameterized using a few empirical orthogonal function(EOF)coefficients.However,when the experimental area is poorly known or highly variable,the adaptability of the EOFs will be significantly reduced.In this study,a new set of basis functions,generated by combining the internal-wave eigenmodes with the average temperature gradient,is developed for characterizing the temperature perturbations.Temperature profiles recorded by a thermistor chain in the South China Sea in 2015 are processed and analyzed.Compared to the EOFs,the new set of basis functions has higher reconstruction accuracy and adaptability;it is also more stable in ocean regions that have internal waves.展开更多
In this paper, the diffraction of water waves by a vertically floating cylinder in a two-layer fluid of a finite depth is studied. Analytical expressions for the hydrodynamic loads on the vertically floating cylinder ...In this paper, the diffraction of water waves by a vertically floating cylinder in a two-layer fluid of a finite depth is studied. Analytical expressions for the hydrodynamic loads on the vertically floating cylinder are obtained by use of the method of eigenfunction expansions. The hydrodynamic loads on the vertically floating cylinder in a two-layer fluid inelude not only the surge, heave and pitch exciting forces due to the incident wave of the surface-wave mode, but also those due to the incident wave of the internal-wave mode. This is different from the case of a homogenous fluid. Some given examples show that, for a two-layer fluid system with a small density difference, the hydrodynamic loads for the surface-wave mode do not differ significantly from those due to surface waves in a single-layer fluid, but the hydrodynamic loads for the internal-wave mode are important over a wide range of frequencies. Moreover, also considered are the free surface and interface elevations generated by the diffraction wave due to the incident wave of the surface-wave and interhal-wave modes, and transfer of energy between modes.展开更多
Study of internal-wave and internal-tide deposits is a very young research field in deep-water sedimentology. It has been just twenty years since the first example of internal-wave and internal-tide deposits was ident...Study of internal-wave and internal-tide deposits is a very young research field in deep-water sedimentology. It has been just twenty years since the first example of internal-wave and internal-tide deposits was identified in the stratigraphic record. Since that time, Chinese scholars have made unremitting efforts and gained some significant research achievements in this field. This paper briefly outlines the history and main achievements of research of internal-wave and internal-tide deposits in China, describes depositional charac-teristics, sedimentary successions, types of lithofacies, and depositional models of internal-wave and internal-tide deposits identified mainly from ancient strata, and summarizes the existing problems in this research field. New advances in marine physics should be applied to research of the subject of internal-wave and internal-tide deposition, whereas the sedimentary characteristics of internal-wave and internal-tide deposits may be used to deduce the physical processes of their creation. Flume experiments on internal-wave and internal-tide deposition should also be put in practice as often as possible, so that the mechanisms of internal-wave and internal-tide deposition can be explored.展开更多
We are glad to know that our paper ＂Review of research in internal-wave and internal-tide deposits of China＂ （Gao et al., 2013） published in Journal of Palaeogeography has attracted close attention of internationa...We are glad to know that our paper ＂Review of research in internal-wave and internal-tide deposits of China＂ （Gao et al., 2013） published in Journal of Palaeogeography has attracted close attention of international peers, and we noted that Shanmugam has provided a critical assessment of our paper. He claimed that ＂interpretations of ten ancient exam- ples in China and one in the central Appalachians （USA） as deep-water deposits of internal waves and internal tides are unsustainable＂, among many other comments and criticisms, and he concluded that ＂any interpretation of ancient strata as deposits of internal waves and internal tides is premature＂. This article is aimed at responding to his major criticisms. We believe that constructive discussions will benefit the development of the study in internal-wave and internal-tide deposits. Unfortunately, Shanmugam seems not to follow this line of scientific criticism, but is trying to reject all research results in this subject based on his illogical and inconsistent reasoning, and distortion of others＇ points of view. In this article, with facts and evidences, we will refuse the main wrong assertions of Shanmugam＇s, for example, ＂the use of bidirectional cross-bedding as evidence for deposition by baroclinic currents in outcrop studies is sedimentologically erroneous ＂ and ＂any interpretation of ancient strata as deposits of internal waves and internal tides is premature＂. We will also use typical characteristics of the ancient examples to demonstrate that they are certainly not turbidites, or contourites, or tsunami-related deposits, but internal-wave and internal-tide deposits as the most plausible to defend the rationality of our interpretation in our previous papers.展开更多
An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as ...An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as well as the wave excitation forces of the circular cylinder were obtained by an eigenfunction expansion method. The hydrodynamic forces on the bottom-mounted circular cylinder in a two-layer fluid include not only the added mass and damping coefficients, but also the wave forces of the surface and internal-wave modes. This is different from the case of a homogenous fluid. Some examples were given, showing that density stratification can have a relative large effect on these hydrodynamic forces over a wide range of frequencies.展开更多
基金The Natural Science Foundation of Shandong Province of China under contract Nos ZR2022MA051 and ZR2020MA090the Fund of China Postdoctoral Science Foundation under contract No.2020M670891+1 种基金the Shandong University of Science and Technology Research Fund under contract No.2019TDJH103the Talent Introduction Plan for Youth Innovation Team in Universities of Shandong Province(Innovation Team of Satellite Positioning and Navigation).
文摘The shallow-water temperature profile is typically parameterized using a few empirical orthogonal function(EOF)coefficients.However,when the experimental area is poorly known or highly variable,the adaptability of the EOFs will be significantly reduced.In this study,a new set of basis functions,generated by combining the internal-wave eigenmodes with the average temperature gradient,is developed for characterizing the temperature perturbations.Temperature profiles recorded by a thermistor chain in the South China Sea in 2015 are processed and analyzed.Compared to the EOFs,the new set of basis functions has higher reconstruction accuracy and adaptability;it is also more stable in ocean regions that have internal waves.
基金This project was financially supported by the National Natural Science Foundation of China(Grant No.10572092)the High Technology Research and Development Programof China(863Program,Grant Nos.2006AA09Z352 and 2006AA09196-6)
文摘In this paper, the diffraction of water waves by a vertically floating cylinder in a two-layer fluid of a finite depth is studied. Analytical expressions for the hydrodynamic loads on the vertically floating cylinder are obtained by use of the method of eigenfunction expansions. The hydrodynamic loads on the vertically floating cylinder in a two-layer fluid inelude not only the surge, heave and pitch exciting forces due to the incident wave of the surface-wave mode, but also those due to the incident wave of the internal-wave mode. This is different from the case of a homogenous fluid. Some given examples show that, for a two-layer fluid system with a small density difference, the hydrodynamic loads for the surface-wave mode do not differ significantly from those due to surface waves in a single-layer fluid, but the hydrodynamic loads for the internal-wave mode are important over a wide range of frequencies. Moreover, also considered are the free surface and interface elevations generated by the diffraction wave due to the incident wave of the surface-wave and interhal-wave modes, and transfer of energy between modes.
基金funded by the National Natural Science Foundation of China (No.40672071 and 41072086)the Research Fund for the Doctoral Program of Higher Education in China (No.20104220110002)
文摘Study of internal-wave and internal-tide deposits is a very young research field in deep-water sedimentology. It has been just twenty years since the first example of internal-wave and internal-tide deposits was identified in the stratigraphic record. Since that time, Chinese scholars have made unremitting efforts and gained some significant research achievements in this field. This paper briefly outlines the history and main achievements of research of internal-wave and internal-tide deposits in China, describes depositional charac-teristics, sedimentary successions, types of lithofacies, and depositional models of internal-wave and internal-tide deposits identified mainly from ancient strata, and summarizes the existing problems in this research field. New advances in marine physics should be applied to research of the subject of internal-wave and internal-tide deposition, whereas the sedimentary characteristics of internal-wave and internal-tide deposits may be used to deduce the physical processes of their creation. Flume experiments on internal-wave and internal-tide deposition should also be put in practice as often as possible, so that the mechanisms of internal-wave and internal-tide deposition can be explored.
基金supported by the China National Natural Science Foundation (Nos.40672071 and 41072086)the Research Fund for the Doctoral Program of Higher Education in China (No.20104220110002)
文摘We are glad to know that our paper ＂Review of research in internal-wave and internal-tide deposits of China＂ （Gao et al., 2013） published in Journal of Palaeogeography has attracted close attention of international peers, and we noted that Shanmugam has provided a critical assessment of our paper. He claimed that ＂interpretations of ten ancient exam- ples in China and one in the central Appalachians （USA） as deep-water deposits of internal waves and internal tides are unsustainable＂, among many other comments and criticisms, and he concluded that ＂any interpretation of ancient strata as deposits of internal waves and internal tides is premature＂. This article is aimed at responding to his major criticisms. We believe that constructive discussions will benefit the development of the study in internal-wave and internal-tide deposits. Unfortunately, Shanmugam seems not to follow this line of scientific criticism, but is trying to reject all research results in this subject based on his illogical and inconsistent reasoning, and distortion of others＇ points of view. In this article, with facts and evidences, we will refuse the main wrong assertions of Shanmugam＇s, for example, ＂the use of bidirectional cross-bedding as evidence for deposition by baroclinic currents in outcrop studies is sedimentologically erroneous ＂ and ＂any interpretation of ancient strata as deposits of internal waves and internal tides is premature＂. We will also use typical characteristics of the ancient examples to demonstrate that they are certainly not turbidites, or contourites, or tsunami-related deposits, but internal-wave and internal-tide deposits as the most plausible to defend the rationality of our interpretation in our previous papers.
基金Project supported by the Foundation of the Excellent State Key Laboratory (Grant No. 50323004) the KSJ Foundation of the Education Ministry of China.
文摘An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as well as the wave excitation forces of the circular cylinder were obtained by an eigenfunction expansion method. The hydrodynamic forces on the bottom-mounted circular cylinder in a two-layer fluid include not only the added mass and damping coefficients, but also the wave forces of the surface and internal-wave modes. This is different from the case of a homogenous fluid. Some examples were given, showing that density stratification can have a relative large effect on these hydrodynamic forces over a wide range of frequencies.
