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721.
Kalyan Kumar Bagchi Sukla Mukherjee Lokenath Debnath 《Pure and Applied Geophysics》1973,111(1):2255-2263
Summary With the aid of the generalized function method, a study is made of the linearized theory of transient development of capillary-gravity waves in an inviscid, incompressible and homogeneous liquid of finite and infinite depth due to an arbitrary oscillating source situated at a finite depth below the undisturbed free surface of the liquid. The initial value problem is solved by using Laplace-Fourier transforms combined with asymptotic methods. The asymptotic solution is found to consist of the steady state and the transient components which are independently modified by surface tension. The latter decays more rapidly as timet due to the presence of surface tension than in the case where surface tension is neglected. It is predicted that the principal effect of surface tension is to increase both the phase and group velocity of the waves and make the energy more readily available among the rapidly travelling progressive surface waves. In addition to the effects of surface tension on the physical properties of the wave motions, our method of solution provides an interesting illustration of the applicability of generalized functions in water wave phenomena. 相似文献
722.
Summary The object of the present paper is to investigate the propagation of surface waves on a non-homogeneous aeolotropic cylindrical shell surrounded by vacuum. The elastic constantsc
ij
(i, j=1,2...) and density of the material of the shell are assumed to be of the form
and
respectively, where ij, 0 are constants andk
1,k
2 are any integers. 相似文献
723.
The Athgarh Sandstone (Upper Gondwana) of Jurassic age exposed in Orissa on the southeastern margin of India comprises almost horizontal medium- to coarse-grained pebbly sandstone interbedded with thin layers of white clay and carbonaceous shale. The cross-bedded sandstone beds within the formation display tabular cross-bedding, having an average thickness of 30 cm and average inclination of 13°. The mean foreset azimuth is 128° (nearly southeast). A total of 537 measurements of cross-beddings from 28 localities, over an area of 500 sq.km, were taken.The study of cross-bed data indicates transportation of sediments by water currents flowing in a southeasterly direction during the deposition of the Athgarh Sandstone. The mean azimuth, thickness and inclination of the cross-beds and sample variance of the area indicate a fluviatile environment of deposition. The dispersal pattern of the currents in the southeastern part of the area suggests proximity to the shore line. 相似文献
724.
Tapan Kumar De 《Pure and Applied Geophysics》1968,70(1):18-21
Summary Love waves in a half space with one homogeneous elastic layer overlying a semiinfinite medium having elastic properties varying with depth has been considered. The frequency equation for small wave lengths has been obtained, considering general variation, and has been shown to involve the first three derivatives of the rigidity of the heterogeneous medium at its interface with the homogeneous layer. 相似文献
725.
A S K Nair G Sankar S Nalina Kumar 《Journal of the Indian Society of Remote Sensing》1993,21(3):151-156
The coastal zone of Kerala with moderate energy, monsoonal-storm-dominated wave climate, together with a microtidal range, falls under the major tectonic class of the Amerotrailing edge coasts. In order to have an effective management of this coastal zone, one requires detailed information on various types of coastal landforms and the related processes acting on them. Coastal inlets are one among such landforms, which are relatively short and narrow tidal channels connecting bays and lagoons to the ocean. Coastal inlets and the related landforms form an important type of coastal feature. An examination of coastal maps from any area in the world will reveal that coastal inlets are of migratory and offset in nature. In the present study the migration pattern and offset behaviour of some of the inlets of Kerala coast have been examined using IRS-IA LISS II data and Survey of India topographic sheets. The study reveals that geocoded IRS-IA LISS II data could provide accurate geometrical information which may considerably minimise the field check. 相似文献
726.
This paper deals with a new family of coupled wave equations which are basically nonlinear in nature. An analyt-ical study enables us to show that these equations exhibit solitary wave profiles. Finally some remarks are drawn from the standpoint of atmospheric problem. 相似文献
727.
Quantitative precipitation forecasting (QPF) has been attempted over the Narmada Catchment following a statistical approach.
The catchment has been divided into five sub-regions for the development of QPF models with a maximum lead-time of 24 hours.
For this purpose the data of daily rainfall from 56 raingauge stations, twice daily observations on different surface meteorological
parameters from 28 meteorological observatories and upper air data from 11 aerological stations for the nine monsoon seasons
of 1972–1980 have been utilized. The horizontal divergence, relative vorticity, vertical velocity and moisture divergence
are computed using the kinematic method at different pressure levels and used as independent variables along with the rainfall
and surface meteorological parameters. Multiple linear regression equations have been developed using the stepwise procedure
separately with actual and square root and log-transformed rainfall using 8-year data (1972–1979). When these equations were
verified with an independent data for the monsoon season of 1980, it was found that the transformed rainfall equations fared
much better compared to the actual rainfall equations. The performance of the forecasts of QPF model compared to the climatological
and persistence forecasts has been assessed by computing the verification scores using the forecasts for the monsoon season
of 1980. 相似文献
728.
Rabindra Kumar Bhattacharyya 《Pure and Applied Geophysics》1976,114(4):639-646
Summary The body wave propagation in granular medium is discussed in two sections. In Section I, the solutions of general equations of granular medium involving displacement vector and rotation vector are shown to be dependent on the solutions of four different equations. In Section II, the plane wave propagation is studied, showing the dispersion and dissipation of body waves in the granular medium. 相似文献
729.
730.
The relationship between point cloudiness and sunshine derived cloud cover in India is investigated using data collected from 33 stations. It has been found that point cloudiness, in general, overestimates sunshine derived cloud cover. The latitudinal dependence of the overestimation is discussed. The significance of the precise quantification of cloudiness in radiation budget studies is briefly mentioned. 相似文献