scholarly journals Inclusion of additional energy dissipation due to plunging breakers in parametric type wave models

2013 ◽  
Vol 82 ◽  
pp. 1-8
Author(s):  
Alireza Jafari ◽  
Nick Cartwright ◽  
Amir Etemad-Shahidi ◽  
Mahnaz Sedigh
Keyword(s):  
Energy Dissipation ◽  
Additional Energy ◽  
Type Wave ◽  
Wave Models

scholarly journals Energy-Dissipation Limits in Variance-Based Computing

2018 ◽  
Vol 17 (02) ◽  
pp. 1850013
Author(s):  
Sri Harsha Kondapalli ◽  
Xuan Zhang ◽  
Shantanu chakrabartty
Keyword(s):  
Energy Dissipation ◽  
Thermal Noise ◽  
Operating Conditions ◽  
Superior Performance ◽  
Energy Scavenging ◽  
Logic Device ◽  
Additional Energy ◽  
Fundamental Limits ◽  
Bit Flip ◽  
Theoretical Results

Variance-based logic (VBL) uses the fluctuations or the variance in the state of a particle or a physical quantity to represent different logic levels. In this paper, we show that compared to the traditional bi-stable logic representation, the variance-based representation can theoretically achieve a superior performance trade-off (in terms of energy dissipation and information capacity) when operating at fundamental limits imposed by thermal noise. We show that, in addition to the universal KT ln(1/[Formula: see text]) energy dissipation required for a single bit flip, a bi-stable logic device needs to dissipate at least 4.35[Formula: see text]KT/bit of energy, whereas under similar operating conditions, a VBL device reduces the additional energy dissipation requirements down to sub-KT/bit. These theoretical results are generally enough to be applicable to different instantiations and variants of VBL ranging from digital processors based on energy-scavenging or to processors based on the emerging valleytronic devices.

On Higher-Order Boussinesq-Type Wave Models

2016 ◽  
Vol 142 (1) ◽  
pp. 04015011 ◽  
Author(s):  
Constantine D. Memos ◽  
Georgios Th. Klonaris ◽  
Michalis K. Chondros
Keyword(s):  
Higher Order ◽  
Type Wave ◽  
Wave Models

Additional Energy Dissipation of Vehicles on a Gradient Road

2013 ◽  
Vol 361-363 ◽  
pp. 2304-2307
Author(s):  
Rui Ling Yu
Keyword(s):  
Numerical Simulation ◽  
Energy Consumption ◽  
Energy Dissipation ◽  
Energy Loss ◽  
Additional Energy ◽  
Energy Consumption Model ◽  
Consumption Model

The additional energy consumption model of vehicles on a gradient road is introduced in this paper. The numerical simulation of the model shows that the additional energy consumption varies with the different slope. Larger solpe means less additional energy loss on a uphhill road while it is the contrary tendency on the downhill road. The analysis of the simulation result is consistent with the actual.

scholarly journals Spectral wave energy dissipation due to under-ice turbulence

2020 ◽  
Author(s):  
Agnieszka Herman
Keyword(s):  
Energy Dissipation ◽  
Sea Ice ◽  
Wave Energy ◽  
Source Term ◽  
Discrete Element Modeling ◽  
Sea Ice Concentration ◽  
Turbulent Dissipation ◽  
Wave Energy Dissipation ◽  
Analogous Model ◽  
Wave Models

AbstractDissipation within the turbulent boundary layer under sea ice is one of many processes contributing to wave energy attenuation in ice-covered seas. Although recent observations suggest that the contribution of that process to the total energy dissipation is significant, its parameterizations used in spectral wave models are based on rather crude, heuristic approximations. In this paper, an improved source term for the under-ice turbulent dissipation is proposed, taking into account the spectral nature of that process (as opposed to parameterizations based on the so-called representative wave), as well as effects related to sea ice concentration and floe-size distribution, formulated on the basis of the earlier results of discrete-element modeling. The core of the new source term is based on an analogous model for dissipation due to bottom friction derived by Weber (J. Fluid Mech, 1991). The shape of the wave energy attenuation curves and frequency-dependence of the attenuation coefficients are analyzed in detail for compact sea ice. The role of floe size in modifying the attenuation intensity and spectral distirbution is illustrated by calibrating the model to observational data from a sudden sea ice break-up event in the marginal ice zone.

Energy Analysis of Piezoelectric-Actuated Structures Driven by Linear Amplifiers

1999 ◽  
Author(s):  
Donald J. Leo
Keyword(s):  
Energy Dissipation ◽  
Piezoelectric Actuator ◽  
Supply Voltage ◽  
Mechanical Load ◽  
Minimum Energy ◽  
Electromechanical System ◽  
Driving Voltage ◽  
Driving Frequency ◽  
Additional Energy ◽  
Energy Dissipated

Abstract Energy expressions for a piezoelectric actuator coupled to a resonant mechanical load are analyzed for the purpose of determining the energy requirements of controlled structures. The analysis illustrates that the energy dissipated within the linear amplifier is a function of four parameters: the driving frequency, the piezoelectric coupling coefficient, the relative stiffness of the actuator and load, and the amplifier supply voltage. The piezoelectric actuator and the mechanical load are assumed to be lossless to highlight the relationship between energy dissipated within the amplifier and the energy stored in the actuator. For a specific frequency, the minimum energy dissipation within the amplifier is equal to twice the stored electrical energy in the piezoelectric when the amplifier voltage is equal to the driving voltage of the actuator. Additional energy is dissipated within the amplifier when the supply voltage is greater than the driving voltage. In the case when the actuator displacement is constant as a function of frequency, the energy dissipation in the amplifier decreases near the resonance of the coupled electromechanical system and reaches a minimum when the piezoelectric charge due to the applied voltage is equal and opposite to the charge induced by the load. The steady-state amplitude of the charge, and hence the actuator current, is equal to zero at this frequency. The results illustrate that energy dissipation is minimized when the actuator is operated at near the resonance or antiresonance of the coupled electromechanical system.

Wave Transmission, Reflection and Energy Dissipation Characteristics of Floating and Fixed Pontoon Type Wave Barriers in Random Wave Fields

2014 ◽  
Author(s):  
Neelamani Subramaniam ◽  
K. Al-Banaa
Keyword(s):  
Energy Dissipation ◽  
Water Depth ◽  
Incident Wave ◽  
Wave Transmission ◽  
Random Wave ◽  
Relative Width ◽  
Transmission Coefficients ◽  
Type Wave ◽  
Short Period ◽  
Wide Range

Wave transmission, reflection and dissipation characteristics of floating and partially immersed fixed pontoon-type barriers dictate its optimal design. Model scaled experimental investigations were carried out on two different types of wave barriers; one, a floating slack moored pontoon barrier and another, a fixed partially immersed pontoon barrier. The hydrodynamic performances for a wide range of random wave conditions are assessed. The draft of both the pontoon models is kept constant with 12.66% of water depth. JONSWAP spectra was used for random wave generation. The investigations were carried out for incident wave steepness, His/Lp in the range of 0.007 to 0.097, relative water depth, d/Lp in the range of 0.093 to 0.452 and relative width of the breakwater, B/Lp in the range of 0.133 to 0.646. It was found from this study that increasing the relative width of the wave barrier could reduce the wave transmission coefficients and increase the wave reflection and energy dissipation coefficients for both the types of wave barriers. For floating barrier, for short period waves (B/Lp of 0.5 to 0.6), the transmission coefficients were in the range of 0.25 to 0.3 and for long period waves (B/Lp of 0.13 to 0.2), the transmission coefficients were in the range of 0.8 to 0.85. Fixing the barrier in space help to reduce the wave transmission to an extent of 10% to 15%, especially for the long waves. For d/Lp in the range of 0.093 to 0.452, for fixed barrier, the reflection coefficients were in the range of 0.6 to 0.8; whereas for floating barrier, it was only in the range of 0.3 to 0.6. It was found that the wave energy dissipation coefficient is better for floating barrier (0.4 to 0.8) compared to fixed barrier (0.2 to 0.5). For a design wave length of 40 m, in order to reduce 50%, 60%, and 70% of the incident wave height on the lee side, a floating pontoon barrier with width of 17.2 m, 21.6 m and 26.0 m respectively would be needed. For the same condition, barrier widths of 12.4 m, 18.8 m, and 26.0 m would be needed for a partially immersed fixed barrier with a draft of 12.66% of water depth. The data from this study will be useful for the design of floating, as well as partially immersed fixed pontoon type wave barriers.

scholarly journals Snow Temperature Behind Sliding Skis as an Indicator for Frictional Meltwater

2021 ◽  
Vol 7 ◽  
Author(s):  
Hasler M ◽  
Jud W ◽  
Nachbauer W
Keyword(s):  
Energy Dissipation ◽  
Heat Flow ◽  
Large Scale ◽  
Experimental Studies ◽  
Infrared Camera ◽  
Contact Spot ◽  
Snow Surface ◽  
Snow Melting ◽  
Additional Energy ◽  
Snow Temperature

For many years, a frictional meltwater film has been assumed to be the reason for the low friction between skis and snow, but experimental studies have been inconclusive. Therefore, the aim of our study was to find indications or evidence for the presence of frictional meltwater. The friction between snow at −4°C and an XC ski as well as a flat ski was measured on a large-scale linear snow tribometer at realistic skiing speeds from 5 to 25 m/s. We used an infrared camera to analyze the snow temperature behind the skis. From the maximum snow surface temperature, we estimated the temperature at the spots where ski and snow contacted. Assuming that the contact spot temperature does not notably exceed 0°C, we calculated the relative contact area between ski and snow. Maximum snow surface temperatures were very close to 0°C. Given that not the entire snow surface is in contact with the ski, this finding is a strong indication for snow melting. Heat flow considerations led to the conclusion that there must be energy dissipation beyond the heat flow into ski and snow. The most obvious mechanism for the additional energy dissipation is snow melting. Presuming that the contact spot temperatures are at most slightly above 0°C, we calculated relative contact areas of 21–98%. Previous research has reported much lower values; however, most studies were conducted under conditions that are not realistic for skiing.

FEM Analysis of Concrete Filled Square Steel Tubular Columns with Energy Dissipation Plate

2012 ◽  
Vol 256-259 ◽  
pp. 666-669
Author(s):  
Cun Hui ◽  
Wan Lin Cao
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Bearing Capacity ◽  
Fem Analysis ◽  
Seismic Energy ◽  
Element Model ◽  
Additional Energy ◽  
Tubular Columns ◽  
Structural Measure ◽  
Cfst Columns

In order to improve the seismic energy dissipation performance of concrete filled square steel tubular (CFST) columns, the structural measure about puting the additional energy dissipation plat at the bottom of the CFST columns where bears more stress, was proposed. Finite element anylsis of 10 CFST columns with different structural measure were performed under the same axial compression, selecting the thickness and height of the energy dissipation plate as parameters. On the basis of finite element anylasis, this paper, which obtained load-displacement curves of each finite element model, analyzed and compared the bearing capacity of each model. The results show that: comparing to the ordinary CFST columns, the columns with energy dissipation plat show better about bearing capacity and seismic performance, the height of the energy dissipation has a significant effect on bearing capacity but the thickness has less impact.

Nonlinear FEM Simulation of Bottom Strengthened Concrete Filled Circular Steel Tubular Columns

2012 ◽  
Vol 256-259 ◽  
pp. 620-623
Author(s):  
Cun Hui ◽  
Wan Lin Cao ◽  
Hong Ying Dong
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Seismic Capacity ◽  
Nonlinear Fem ◽  
Additional Energy ◽  
Axial Compression Ratio ◽  
Cfst Columns

The structural measures about puting the additional energy dissipation plat at the bottom of the CFST columns where bears more stress, was proposed to improve the seismic energy dissipation performance of concrete filled circular steel tubular (CFST) columns. Selecting the axial compression ratio and height of the energy dissipation plate as parameters, finite element anylsis of 8 circular CFST columns with different structural measure were performed. On the basis of finite element anylasis results, this paper, which obtained load-displacement curves of each finite element model, analyzed and compared the bearing capacity of each model. The results show that: comparing to the ordinary circular CFST columns, the columns with energy dissipation plat show much better performence about bearing capacity and seismic capacity, the height of the energy dissipation has a great effect on bearing capacity but the bearing capacity is inversely proportional to the axial compression ratio.

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