scholarly journals PERFORMANCE OF POROUS MARINE STRUCTURES OF SINGLE AND DOUBLE PERFORATED SEAWALLS IN REGULAR OBLIQUE WAVES

2017 ◽  
pp. 8
Author(s):  
Nadji Chioukh ◽  
Mohamed Boukhari ◽  
Yalçın Yüksel ◽  
Benameur Hamoudi
Keyword(s):  
Wave Energy ◽  
Domain Boundary ◽  
Least Square Method ◽  
Diffraction Theory ◽  
Boundary Integral ◽  
Least Square ◽  
Marine Structures ◽  
Oblique Waves ◽  
Wave Energy Dissipation ◽  
Analytical Series

In the present paper we examine the performance of two very common types of wave absorbing porous marine structures under regular oblique waves. The first structure consists of a single perforated vertical seawall, whereas the second consists of two perforated vertical seawalls creating what is called a chamber system (Jarlan type breakwater). The structures are surface piercing thus eliminating wave overtopping. Two methods are used for the present investigation. In the first method the problem of the interaction of obliquely incident linear waves upon a pair of porous vertical seawalls is first formulated in the context of the linear diffraction theory. The resulting boundary integral equation, which is matched with far-field solutions represented in terms of analytical series with unknown coefficients, and appropriate boundary conditions at the free surface, seabed and seawalls, is then solved numerically using the multi-domain boundary element method. In the second method a semi-analytical solution is developed by means of the eigenfunction expansions and a minimization approach using a least square method. In both methods the dissipation of the wave energy due to the presence of the perforated seawalls is represented by a simple yet effective relation in terms of the porosity parameter appropriate for thin perforated walls. The results are presented in terms of reflection and transmission coefficients, and the wave energy dissipation. Effects of the incident wave angles, porosities and depths of the walls and other major parameters of interest are explored.

Analytical study of oblique wave scattering by a submerged pile–rock breakwater

2017 ◽  
Vol 233 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Ai-jun Li ◽  
Hua-jun Li ◽  
Yong Liu
Keyword(s):  
Energy Dissipation ◽  
Analytical Solution ◽  
Wave Energy ◽  
Structural Parameters ◽  
Domain Boundary ◽  
Linear Potential ◽  
Wave Energy Dissipation ◽  
Special Cases ◽  
Linear Potential Theory ◽  
Incident Waves

This study examines the scattering of obliquely incident waves by a submerged pile–rock breakwater, which consists of two rows of closely spaced piles and a rock core between them. Based on linear potential theory, a closed-form analytical solution for the present problem is developed using matched eigenfunction expansions. The analytical solution is novel because of the new submerged pile–rock-type breakwater. The analytical solution is confirmed by an independently developed multi-domain boundary element method solution. The analytical solution is also compared with experimental data for three special cases of the present breakwater. Numerical examples are presented to investigate the effects of structural parameters and wave parameters on the reflection, transmission and energy loss coefficients of the breakwater. It is found that the wave energy dissipation by the submerged pile–rock breakwater is mainly contributed by the rock core, and only a small part of wave energy dissipation is due to the closely spaced piles.

scholarly journals Combining Multi-body Dynamics and Potential Flow Simulation Methods to Model a Wave Energy Converter

2018 ◽  
Author(s):  
Christopher McComb ◽  
Michael Lawson ◽  
Yi-Hsiang Yu
Keyword(s):  
Frequency Domain ◽  
Wave Energy ◽  
Time Domain ◽  
Domain Boundary ◽  
Flow Simulation ◽  
Primary Objective ◽  
Boundary Integral ◽  
Body Dynamics ◽  
Numerical Tool ◽  
Multi Body

Numerical simulations that predict the dynamics and performance of wave energy converters (WECs) require the simulation of complex fluid-structure interactions between a WEC device and the wave environment. Navier- Stokes computational fluid dynamics (CFD) simulations and fully time-domain boundary integral equation methods (BIEMs) can be coupled with multi-body dynamics solvers to simulate these problems. However, the computational resources that are required to perform these types of high-fidelity simulations are significant, precluding the use of CFD and time-domain BIEM for design optimization. One method for reducing the numerical complexity of WEC simulations is to model the hydrodynamics using frequency- domain simulations, while model the dynamic motion of the WEC device in the time-domain using multi-body dynamics methods.The primary objective of the work presented herein is to develop such a numerical tool using the multi-body solver SimMechanics and the frequency-domain hydrodynamics code WAMIT. The numerical tool was developed so that WEC devices comprised of arbitrarily connected bodies, power-take-off (PTO) systems, and mooring systems can be simulated in operational sea states, where the wave environment can be modeled under linear assumptions. The remainder of this paper describes the development and verification of the numerical tool.

Direct Assessment of Effective Renal Plasma Flow from Renoscintigraphy with a Gamma Camera and an On-Line Computer

1981 ◽  
Vol 20 (06) ◽  
pp. 274-278
Author(s):  
J. Liniecki ◽  
J. Bialobrzeski ◽  
Ewa Mlodkowska ◽  
M. J. Surma
Keyword(s):  
Count Rate ◽  
Renal Plasma Flow ◽  
Early Period ◽  
Least Square Method ◽  
Least Square ◽  
Uptake Coefficient ◽  
Positive Linear Correlation ◽  
On Line ◽  
Best Fit ◽  
Plasma Activity

A concept of a kidney uptake coefficient (UC) of 131I-o-hippurate was developed by analogy from the corresponding kidney clearance of blood plasma in the early period after injection of the hippurate. The UC for each kidney was defined as the count-rate over its ROI at a time shorter than the peak in the renoscintigraphic curve divided by the integral of the count-rate curve over the "blood"-ROI. A procedure for normalization of both curves against each other was also developed. The total kidney clearance of the hippurate was determined from the function of plasma activity concentration vs. time after a single injection; the determinations were made at 5, 10, 15, 20, 30, 45, 60, 75 and 90 min after intravenous administration of 131I-o-hippurate and the best-fit curve was obtained by means of the least-square method. When the UC was related to the absolute value of the clearance a positive linear correlation was found (r = 0.922, ρ > 0.99). Using this regression equation the clearance could be estimated in reverse from the uptake coefficient calculated solely on the basis of the renoscintigraphic curves without blood sampling. The errors of the estimate are compatible with the requirement of a fast appraisal of renal function for purposes of clinical diagknosis.

PENGARUH KNOWLEDGE MANAGEMENT, KOMPETENSI, MOTIVASI TERHADAP KINERJA KARYAWAN

2015 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Miftahol Arifin
Keyword(s):  
Knowledge Management ◽  
Linear Regression ◽  
Significant Influence ◽  
Employee Performance ◽  
Least Square Method ◽  
Least Square ◽  
Analysis Tool ◽  
Ordinary Least Square ◽  
Competence Motivation ◽  
Performance Analyze

The purpose of this research is to analyze the influence of knowledge management on employee performance, analyze the effect of competence on employee performance, analyze the influence of motivation on employee performance). In this study, samples taken are structural employees PT.centris Kingdom Taxi Yogyakarta. The analysis tool in this study using multiple linear regression with Ordinary Least Square method (OLS). The conclusion of this study showed that the variables of knowledge management has a significant influence on employee performance, competence variables have an influence on employee performance, motivation variables have an influence on employee performance, The analysis showed that the variables of knowledge management, competence, motivation on employee performance.Keywords: knowledge management, competence, motivation, employee performance.

Peristaltic Carreau-Yasuda nanofluid flow and mixed heat transfer analysis in an asymmetric vertical and tapered wavy wall channel

2020 ◽  
Vol 1 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Mohammad Hatami ◽  
◽  
D Jing ◽  
Keyword(s):  
Heat Transfer ◽  
Least Square Method ◽  
Weissenberg Number ◽  
Least Square ◽  
Heat Transfer Analysis ◽  
Phase Method ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Nanoparticles Concentration ◽  
The Right

In this study, two-phase asymmetric peristaltic Carreau-Yasuda nanofluid flow in a vertical and tapered wavy channel is demonstrated and the mixed heat transfer analysis is considered for it. For the modeling, two-phase method is considered to be able to study the nanoparticles concentration as a separate phase. Also it is assumed that peristaltic waves travel along X-axis at a constant speed, c. Furthermore, constant temperatures and constant nanoparticle concentrations are considered for both, left and right walls. This study aims at an analytical solution of the problem by means of least square method (LSM) using the Maple 15.0 mathematical software. Numerical outcomes will be compared. Finally, the effects of most important parameters (Weissenberg number, Prandtl number, Brownian motion parameter, thermophoresis parameter, local temperature and nanoparticle Grashof numbers) on the velocities, temperature and nanoparticles concentration functions are presented. As an important outcome, on the left side of the channel, increasing the Grashof numbers leads to a reduction in velocity profiles, while on the right side, it is the other way around.

Fast noise removal algorithm for HDR image based on least square method

2009 ◽  
Vol 29 (4) ◽  
pp. 994-996
Author(s):  
De-quan SUN ◽  
Jun ZHANG ◽  
Xiao-feng LI ◽  
Hui LI
Keyword(s):  
Least Square Method ◽  
Noise Removal ◽  
Least Square ◽  
Hdr Image

Model-based control of the substrate concentration in an aeration basin using the wastewater level

1998 ◽  
Vol 37 (12) ◽  
pp. 335-342 ◽  
Author(s):  
Jacek Czeczot
Keyword(s):  
Substrate Concentration ◽  
Consumption Rate ◽  
Least Square Method ◽  
Estimation Procedure ◽  
Adaptive Controller ◽  
Open Loop ◽  
Least Square ◽  
Substrate Consumption ◽  
Model Based ◽  
Effluent Flow Rate

This paper deals with the minimal-cost control of the modified activated sludge process with varying level of wastewater in the aerator tank. The model-based adaptive controller of the effluent substrate concentration, basing on the substrate consumption rate and manipulating the effluent flow rate outcoming from the aerator tank, is proposed and its performance is compared with conventional PI controller and open loop behavior. Since the substrate consumption rate is not measurable on-line, the estimation procedure on the basis of the least-square method is suggested. Finally, it is proved that cooperation of the DO concentration controller with the adaptive controller of the effluent substrate concentration allows the process to be operated at minimum costs (low consumption of aeration energy).

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