scholarly journals Scattering of interface wave by bottom undulations in the presence of thin submerged vertical wall with a gap

2016 ◽  
Vol 21 (2) ◽  
pp. 303-322
Author(s):  
P. Dolai
Keyword(s):  
Reflection Coefficient ◽  
Vertical Wall ◽  
Finite Depth ◽  
Zero Order ◽  
Wave Number ◽  
Reflection Coefficients ◽  
First Order ◽  
Interface Wave ◽  
Lower Fluid ◽  
Order Reflection

AbstractIn this paper, the problem of interface wave scattering by bottom undulations in the presence of a thin submerged vertical wall with a gap is investigated. The thin vertical wall with a gap is submerged in a lower fluid of finite depth with bottom undulations and the upper fluid is of infinite height separated by a common interface. In the method of solution, we use a simplified perturbation analysis and suitable applications of Green’s integral theorem in the two fluid regions produce first-order reflection and transmission coefficients in terms of integrals involving the shape function describing the bottom undulations and solution of the scattering problem involving a submerged vertical wall present in the lower fluid of uniform finite depth. For sinusoidal bottom undulations, the first-order transmission coefficient vanishes identically. The corresponding first-order reflection coefficient is computed numerically by solving the zero-order reflection coefficient and a suitable application of multi-term Galerkin approximations. The numerical results of the zero-order and first-order reflection coefficients are depicted graphically against the wave number in a number of figures. An oscillatory nature is observed of first-order reflection coefficient due to multiple interactions of the incident wave with bottom undulations, the edges of the submerged wall and the interface. The first-order reflection coefficient has a peak value for some particular value of the ratio of the incident wavelength and the bottom wavelength. The presence of the upper fluid has some significant effect on the reflection coefficients.

scholarly journals Reflection of water waves in the presence of surface tension by a nearly vertical porous wall

1998 ◽  
Vol 39 (3) ◽  
pp. 308-317 ◽  
Author(s):  
A. Chakrabarti ◽  
T. Sahoo
Keyword(s):  
Surface Tension ◽  
Water Waves ◽  
Vertical Wall ◽  
Porous Wall ◽  
Finite Depth ◽  
Regularity Property ◽  
Positive Real ◽  
First Order ◽  
The Subject ◽  
First Order Correction

AbstractIn the present paper the problem of reflection of water waves by a nearly vertical porous wall in the presence of surface tension has been investigated. A perturbational approach for the first-order correction has been employed as compared with the corresponding vertical wall problem. A mixed Fourier transform together with the regularity property of the transformed function along the positive real axis has been used to obtain the potential functions along with the reflection coefficients up to first order. Whilst the problem of water of infinite depth is the subject matter of the present paper, a similar approach is applicable to problems associated with water of finite depth.

scholarly journals SURFACE WAVE SCATTERING BY AN ELASTIC PLATE SUBMERGED IN WATER WITH UNEVEN BOTTOM

2020 ◽  
Vol 25 (3) ◽  
pp. 323-337
Author(s):  
Souvik Kundu ◽  
Rupanwita Gayen
Keyword(s):  
Reflection Coefficient ◽  
Elastic Plate ◽  
Flexural Rigidity ◽  
Bottom Topography ◽  
Integral Theorem ◽  
First Order ◽  
Bottom Undulation ◽  
Rigidity Parameter ◽  
Vertical Elastic Plate ◽  
Order Reflection

Wave interaction with a vertical elastic plate in presence of undulating bottom topography is considered, assuming linear theory and utilizing simple perturbation analysis. First order correction to the velocity potential corresponding to the problem of scattering by a vertical elastic plate submerged in a fluid with a uniform bottom is obtained by invoking the Green’s integral theorem in a suitable manner. With sinusoidal undulation at the bottom, the first-order transmission coefficient (T1) vanishes identically. Behaviour of the first order reflection coefficient (R1) depending on the plate length, ripple number, ripple amplitude and flexural rigidity of the plate is depicted graphically. Also, the resonant nature of the first order reflection is observed at a particular value of the ratio of surface wavelength to that of the bottom undulations. The net reflection coefficient due to the joint effect of the plate and the bottom undulation is also presented for different flexural rigidity of the plate. When the rigidity parameter is made sufficiently large, the results for R1 reduce to the known results for a surface piercing rigid plate in water with bottom undulation.

scholarly journals Oblique interface-wave diffraction by a small bottom deformation in two superposed fluids

1996 ◽  
Vol 19 (2) ◽  
pp. 363-370 ◽  
Author(s):  
B. N. Mandal ◽  
U. Basu
Keyword(s):  
Integral Theorem ◽  
Interface Waves ◽  
First Order ◽  
Two Fluids ◽  
Transmission And Reflection Coefficients ◽  
Bottom Deformation ◽  
Interface Wave ◽  
Lower Fluid ◽  
Superposed Fluids ◽  
Transmission And Reflection

The problem of diffraction of oblique interface-waves by a small bottom deformation of the lower fluid in two superposed fluids has been investigated here assuming linear theory and invoking a simplified perturbation analysis. First order corrections to the velocity potentials in the two fluids are obtained by using the Green's integral theorem in a suitable manner. The transmission and reflection coefficients are evaluated approximately. These reduce to the known results for a single fluid in the absence of the upper fluid.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Area-based speciation kinetic analysis of the multipollutant removal in Constructed Wetlands to enhance its treatment efficiency

2021 ◽  
Author(s):  
Manoj Kumar ◽  
Rajesh Singh
Keyword(s):  
Wastewater Treatment ◽  
Kinetic Analysis ◽  
Constructed Wetlands ◽  
Municipal Wastewater ◽  
Zero Order ◽  
Pollutant Removal ◽  
Municipal Wastewater Treatment ◽  
Treatment Efficiency ◽  
First Order ◽  
Present Study Area

In the present study area-based, pollutant removal kinetic analysis was considered using the Zero-order, first-order decay and efficiency loss (EL) models in the constructed wetlands (CWs) for municipal wastewater treatment....

Supercritical Fluid Deposition of Ruthenium Thin Films: A Kinetic Study

2007 ◽  
Vol 992 ◽  
Author(s):  
Christos F. Karanikas ◽  
James J. Watkins
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Deposition Temperature ◽  
Zero Order ◽  
Measurable Effect ◽  
Deposition Rates ◽  
Reaction Pressure ◽  
Deposition Kinetics ◽  
First Order ◽  
Kinetics Of

AbstractThe kinetics of the deposition of ruthenium thin films from the hydrogen assisted reduction of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5-cyclooctadiene)ruthenium(II), [Ru(tmhd)2cod], in supercritical carbon dioxide was studied in order to develop a rate expression for the growth rate as well as to determine a mechanism for the process. The deposition temperature was varied from 240°C to 280°C and the apparent activation energy was 45.3 kJ/mol. Deposition rates up to 30 nm/min were attained. The deposition rate dependence on precursor concentrations between 0 and 0.2 wt. % was studied at 260°C with excess hydrogen and revealed first order deposition kinetics with respect to precursor at concentrations lower then 0.06 wt. % and zero order dependence at concentrations above 0.06 wt. %. The effect of reaction pressure on the growth rate was studied at a constant reaction temperature of 260°C and pressures between 159 bar to 200 bar and found to have no measurable effect on the growth rate.

Stability of ion–acoustic solitary waves in a multi-species magnetized plasma consisting of non-thermal and isothermal electrons

2009 ◽  
Vol 75 (5) ◽  
pp. 593-607 ◽  
Author(s):  
SK. ANARUL ISLAM ◽  
A. BANDYOPADHYAY ◽  
K. P. DAS
Keyword(s):  
Stability Analysis ◽  
Solitary Wave ◽  
Solitary Waves ◽  
Perturbation Expansion ◽  
Magnetized Plasma ◽  
Wave Number ◽  
First Order ◽  
Zk Equation ◽  
Ion Acoustic Solitary Waves ◽  
Ion Acoustic

AbstractA theoretical study of the first-order stability analysis of an ion–acoustic solitary wave, propagating obliquely to an external uniform static magnetic field, has been made in a plasma consisting of warm adiabatic ions and a superposition of two distinct populations of electrons, one due to Cairns et al. and the other being the well-known Maxwell–Boltzmann distributed electrons. The weakly nonlinear and the weakly dispersive ion–acoustic wave in this plasma system can be described by the Korteweg–de Vries–Zakharov–Kuznetsov (KdV-ZK) equation and different modified KdV-ZK equations depending on the values of different parameters of the system. The nonlinear term of the KdV-ZK equation and the different modified KdV-ZK equations is of the form [φ(1)]ν(∂φ(1)/∂ζ), where ν = 1, 2, 3, 4; φ(1) is the first-order perturbed quantity of the electrostatic potential φ. For ν = 1, we have the usual KdV-ZK equation. Three-dimensional stability analysis of the solitary wave solutions of the KdV-ZK and different modified KdV-ZK equations has been investigated by the small-k perturbation expansion method of Rowlands and Infeld. For ν = 1, 2, 3, the instability conditions and the growth rate of instabilities have been obtained correct to order k, where k is the wave number of a long-wavelength plane-wave perturbation. It is found that ion–acoustic solitary waves are stable at least at the lowest order of the wave number for ν = 4.

LOOP ANTENNA WITH A SEMICONDUCTOR ELEMENT

2021 ◽  
Author(s):  
П.А. ТИТОВЕЦ ◽  
А.И. САТТАРОВА ◽  
А.А. ПИЩЕРКОВ ◽  
Н.С. БЕКУШЕВ
Keyword(s):  
Laser Radiation ◽  
Reflection Coefficient ◽  
Copper Foil ◽  
Loop Antenna ◽  
Laser Source ◽  
Reflection Coefficients ◽  
Building Element ◽  
External Contour ◽  
In Series ◽  
Loop Antennas

Представлены результаты исследований рамочной антенны, в которой подстроечным элементом является фоторезистор, управляемый лазерным излучением. Показано, что использование фоторезистора как элемента внешнего контура рамочной антенны, включенного последовательно, позволяет изменять согласование рамочной антенны с помощью внешнего лазерного источника. Представлены результаты исследований характеристик коэффициента передачи рамочных антенн, состоящих из медной фольги на диэлектрической основе и полупроводникового элемента. Установлено, что при изменении интенсивности лазерного излучения, падающего на полупроводниковый элемент-фоторезистор, изменяется коэффициент отражения рамочной антенны. В диапазоне от 10 МГц до 18ГГц получены зависимости коэффициентов отражения (Su)рамочных антенн с полупроводниковым элементом. Проведено сравнение рамочной антенны и рамочной антенны с фоторезистором. The results of an experiment with a loop antenna, in which the building element is a photoresistor controlled by laser radiation, are presented. It is shown that the use of a photoresistor as an element of the external contour of a loop antenna connected in series makes it possible to change the matching of the loop antenna due to an external laser source. The results of studies of the characteristics of the transmission coefficient of loop antennas consisting of a dielectric copper foil and a semiconductor element are presented. It was found that when the intensity of the laser radiation incident on the semiconductor element-photoresistor changes, the reflection coefficient of the frame antenna changes. In the range of 10 MHz-18 GHz, the dependences of the reflection coefficients (S11) of loop antennas with a semiconductor element are obtained. A comparison is made between a loop antenna and a loop antenna with a photoresistor.

Theory of Short Wave Excitation

1986 ◽  
Vol 30 (03) ◽  
pp. 147-152
Author(s):  
Yong Kwun Chung
Keyword(s):  
Incident Wave ◽  
Characteristic Length ◽  
Finite Depth ◽  
Short Wave ◽  
The Body ◽  
Wave Number ◽  
Floating Body ◽  
Wave Excitation ◽  
Exciting Forces ◽  
Wave Exciting Forces

When the wavelength of the incident wave is short, the total surface potential on a floating body is found to be 2∅ i & O (m-l∅ i) on the lit surface and O (m-l∅ j) on the shadow surface where ~b i is the potential of the incident wave and m the wave number in water of finite depth. The present approximation for wave exciting forces and moments is reasonably good up to X/L ∅ 1 where h is the wavelength and L the characteristic length of the body.

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