徐德伦
海浪和小尺度海-气相互作用
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- 姓名:徐德伦
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学术头衔:
博士生导师
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学科领域:
地理学
- 研究兴趣:海浪和小尺度海-气相互作用
徐德伦,教授,1939年生,山东烟台人。1960年毕业于山东海洋学院物理海洋专业,长期从事海浪和小尺度海-气相互作用的教学和研究工作。1987年晋升为青岛海洋大学(现为中国海洋大学)的副教授;1991年晋升为教授,1995年被评为博士生导师。1982年至1984年和1991年至1992年两次共三年多时间在美国特拉华大学海-气相互作用实验室进修和合作研究。先后主持完成四个和作为主要成员参加完成二个国家自然科学基金项目;作为主要成员参加完成二个国家863项目。至今发表学术论文60余篇,其中20篇被收录入SCI。二十世纪末在国际重要刊物Journal of Physical Oceanography, Journal of Fluid Mechanics 和 Journal of Geophysical Research发表的三篇关于风浪破碎的论文,因从试验和观测上揭示了风浪破碎的一些统计规律和首次建立了以风速和风区长度两者为参量的风浪破碎概率和白冠覆盖率的统计模式而被广泛引用;至今已被SCI论文引用52次,其中包括十几个国家(包括前苏联)的海洋及气象研究者和许多国际著名海洋及气象学家的引用。研究成果“风浪破碎研究”获2002年中国高校科技奖自然科学一等奖(第一获奖人);研究成果“随机波群模拟”获1997年国家教委科技进步三等奖(第一获奖人)。1997年获剑桥国际名人传记中心授予的“二十世纪成就(海洋科学)”奖。编著的《随机海浪理论》一书被教育部审定为首批研究生教学用书之一,2002年由高等教育出版社出版;译著《上层海洋动力学》(美,Phillips著)1984年由科学出版社出版。
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704
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成果数
10
【期刊论文】Statistical simulation of wave groups
徐德伦, Delun Xu, Wei Hou, Meng Zhao & Jin Wu
Applied Ocean Research 15(1993)217-226,-0001,():
-1年11月30日
Wave grouping is analysed by the envelope approach, with envelopes being computed from wave records through the Hilbert transform technique. To specify wave groups, the group height factor and length factor are defined in terms of parameters of both wave and envelope spectral parameters. Based on the analysis and definition, a method is developed to simulate irregularly grouped wave signals with both specified wave and envelope spectra as target. A series of simulated examples is presented to demonstrate the feasibility of the method.
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【期刊论文】Statistical Distribution of Surface Slope in A 3-D Ocean Wave Field*
徐德伦, XU Delun, LIU Xuehai and ZHANG Jun
China Ocean Engineering, Vol.14, No.3, pp.289-296.,-0001,():
-1年11月30日
A joint probability density function (PDF) for surface slopes in two arbitrary directions is derived on the basis of Longuet-Higgins's linear model for three-dimensional (3-D) random wave field, and the correlation moments of surface slopes, as parameters in the PDF, are expressed in terms of directional spectrum of ocean waves, So long as the directional spectrum model is given, these parameters are determined. Since the directional spectrum models proposed so far are mostly parameterized by the wind speed and fetch, this allows for substituting these parameters with the wind speed and fetch. As an example, the wind speed and fetch are taken to be 14m/s and 200km, and the Hasselmann and Donelan directional spectra are, respectively, used to compute these parameters. Some novel results are obtained. One of the interesting results is thai the variances of surface slope in downwind and cross-wind directions determined by the Donelan directional spectra are close to those measured by Cox and Munk (1954). Some discussions are made on these results.
probability density function, surface slope, three-dimensional waves, linear theory
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【期刊论文】Probability of wave breaking and whitecap coverage in a fetch-limited sea
徐德伦, D. Xu, X. Liu, and D. Yu
JOURNAL OF GFOPHYSICAL RESEARCH, VOL.105, NO.C6, PAGES 14,253-14,259, JUNE 15, 2000,-0001,():
-1年11月30日
The analytical model of Snyder and Kennedy [1983] for the whitecap coverage W and that of Srokosz [1985] for the probability of wave breaking B are developed into practically appiicablc forms by closely combining theoretical analysis and data fitting. The database consists of two parts: the data collected Irom published literature and those recently measured in the Bohai Bay, A time-averaging techniquc is used to estimate the fourth spectral moment of the mean Joint North Sea Wave Project spectrum. The resulting expressions are simple, in which W and B depend only on the nondimensional fotch for a fetch-limited sea.
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【期刊论文】On the relationships between the mean wavelength and wave-period of wind waves in deep water
徐德伦, D. Xu*, H. Lu, D. Yu
Applied Ocean Research 21(1999)127-131,-0001,():
-1年11月30日
Relationships between the mean wavelength and mean wave-period of wind waves are derived for fetch-limited and fully developed seas. The derivations start from the Rice solution of zero-crossing problem and use the JONSWAP and Pierson-Moscowitz spectra, respectively. The spectral moments of order 4 involved in the derivations are estimated through a time-averaging technique. Experiments were conducted in a wind-wave channel. Comparisons between the relationships and the experimental results show a favorable agreement.
Mean wave-period, Mean wavelength, Wind waves
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【期刊论文】On the distributions of wave periods, wavelengths, and amplitudes in a random wave field
徐德伦, Delun Xu, Xiang Li, Lizhen Zhang, Ning Xu, and Hongmin Lu
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, C05016,-0001,():
-1年11月30日
[1] On the basis of a narrow-band Gaussian process, two theoretical probability density functions (PDFs) are derived by applying an approximate Hilbert transform to the process represented by a general form. The first PDF is for the joint distribution of the wave period t and amplitude r of sea waves. It has the same merits as the PDF previously derived by Longuet-Higgins [1983], in being asymmetric in t and depending only on the spectral width parameter n, but gains an advantage that it predicts an exactly Rayleigh distribution of r and so facilitates its handling in theory and application in practice. In virtue of the advantage, a relatively simple conditional PDF of t assuming r is derived, which may be used to predict an arbitrarily defined characteristic conditional wave period assuming the wave height from the average wave period. The second PDF is for the joint distribution of wavelengths and amplitudes in a unidirectional Gaussian wave field with narrow spectrum. It has the same form as the first PDF but depends only on the parameter m defined by μ2=m0m4/m2- 1, where mn is the nth moment of spectrum. From this joint PDF, a PDF for the distribution of wavelengths of sea waves is also derived. Numerical simulation and laboratory experiments of wind waves and their results are reported. It is shown that the PDFs derived in this paper give fairly good fits to the simulated data and suitably filtered laboratory data. INDEX TERMS: 0624 Electromagnetics: Guided waves; 3384 Meteorology and Atmospheric Dynamics: Waves and tides; 4263 Oceanography: General: Ocean prediction
joint probability of wave variables,, Hilbert transform,, experiment
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【期刊论文】Maximum Entropy Estimation of n-Year Extreme Waveheights*
徐德伦, XU De-lun, ZHANG Jun and ZHENG Gui-zhen
China Ocean Engineering, Vol.18, No.2, pp.307-314,-0001,():
-1年11月30日
A new method for estimating the n (50 or 100)-year return-period waveheight, namely, the extreme waveheight expected to occur in n years, is presented on the basis of the maximum entropy principle. The main points of the method are as follows: (1) based on the Hamiltonian principle, a maximun entropy probability density function for the extreme waveheight H, f(H)=aHγe-βH4 is derived from a Lagrangian function subject to some necessary and rational constraints; (2) the parameters a, β, and γ in the function are expressed in terms of the mean H, variance V=(H-H-)2 and bias B=(H-H-)3; and (3) with H-, V and B estimated from observed data, the n-year return-period wave height Hn is computed in accordance with the formula 1/1-F(Hn)=n, where F(Hn) is defined as F(Hn)=∫Hnf(H)dH. Examples of estimating the 50 and 100-year return period waveheights by the present method and by some currently used method from observed data acquired from two hydrographic stations are given. A comparison of the estimated results shows that the present method is superior to the others.
maximum entropy, n-year return-period waveheights, Lagrangian function
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【期刊论文】Breaking of Wind-Generated Waves
徐德伦, DELUN MU*, PAUL A. HWANG** AND JIN WU
JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 16,-0001,():
-1年11月30日
Breaking of wind-generated waves was studied in a laboratory, tank. The critical surface slope and global wave steepness for inception of breaking were evaluated. Besides the frequency of occurrence, two other characteristic quantities, height and duration of breaking, were measured. The frequency of breaking was found increase rapidly with wind velocity, following a power law U22. The period of breaking remained about 7% of the wave period at all wind velocities. The height of breaking was about 30% of the wave height. Portions of these results compare favorably with other available measurements.
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【期刊论文】Breaking of wind-generated waves: measurements and characteristics
徐德伦, By PAUL A. HWANG†, DELUN XU‡ AND JIN WU
J. Fluid Mech. (1989), vol.202, pp.177-200,-0001,():
-1年11月30日
A method of using local wave properties to provide a detailed description of breakings in a random wave field is developed. These properties, derived through the Hilbert transform, include the angular frequency, phase velocity, and surfacevelocity components. The breaking characteristics are presented, including the probability of breaking, its time-and lengthscales, its intensity, and the phase of its inception. The time-and lengthscales of breaking events were found to be linearly proportional to the corresponding scales of underlying waves, and to indicate that the breaking region is geometrically similar. Consistent results were obtained from temporal and spatial measurements. Finally, on the basis of these results we have evaluated geometric and kinematic criteria for identifying breaking waves.
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【期刊论文】A Whitecap Coverage Model Based on the Surface Slope For Criterion of Wave Breaking①
徐德伦, Xu Delun*, Yu Dingyong** and Lu Hongmin***
China Ocean Engineering, Vol.12, No.1, pp.73-85.,-0001,():
-1年11月30日
Using the limit surface slope as a criterion of wave breaking, a simple model for estimating the spatial fraction of breaking surface of sea at an instant, which is regarded as the whitecap coverge in this paper, is analytically derived from the probability density of surface slope based on Gaussian statistics. The resulting fraction is found depending on the fourth moment of wave spectum, m4, as well as the critical threshold of surface slope. By expressing the fourth moment in terms of the Neumann spectrum, a formula linking the fraction and wind speed for fully developed sea states is obtianed. Another formula relating the fraction to both wind speed and fetch (or duration) is achieved by expressing m4 in terms of the Krylov spectrum and applying the empirical relationships used in the SMB ocean wave predicting technique. A comparison between these results and the field data of whitecap coverage collected by Monahan and O'Muircheartuigh shows an encouraging agreement.
whitecap coverage, criterion of wave breaking, wind speed, wind fetch, wind duration, fully developed sea state, fetch-limited sea state
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【期刊论文】A Refined Method for Estimating the Annual Extreme Wave Heights at A Project Site1
徐德伦, XU De-lun*, FAN nai-mei and ZHANG Jun
China Ocean Engineering, Vol. 17, No.1, pp. 21-32,-0001,():
-1年11月30日
This paper presents a refined method for estimating the annual extreme wave heights at a coastal or offshore project site on the basis of the data acquired at some nearby routine hydrographic stations. This method is based on the orthogonality principle in linear mean square estimation of stochastic processes. The error of the method is analyzed and compared with that of the conventional method. It is found that the method is able to effectively reduce the error so long as some feasible measures are adopted. A simulated test of the method has been conducted in a large-scale wind-wave flume. The test results are in good agreement with those given by theoretical error analysis. A scheme to implement the method is proposed on the basis of error analysis. The scheme is so designed as to reduce the estimation error as far as possible. This method is also suitable to utilizing satellite wave data for the estimation.
annual extreme wave height, estimation, refined method, simulated test
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