Hydrodynamic damping due to baffles in a rectangular tank

2001 ◽  
Vol 28 (4) ◽  
pp. 608-616 ◽  
Author(s):  
Michael Isaacson ◽  
Sundaralingam Premasiri
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Total Energy ◽  
Earthquake Engineering ◽  
Flow Separation ◽  
Average Rate ◽  
Experimental Measurements ◽  
Hydrodynamic Damping ◽  
Rectangular Tank

The present paper describes the prediction of hydrodynamic damping due to baffles in a fluid-filled rectangular tank or reservoir undergoing horizontal oscillations. The estimation of hydrodynamic damping involves an assessment of the total energy in the fluid associated with sloshing motions and the average rate of energy dissipation due to flow separation around the baffles. Experimental measurements of hydrodynamic damping have been carried out to validate the theoretical model and to investigate the effectiveness of various baffle configurations. Recommendations are made regarding the assessment of hydrodynamic damping in earthquake engineering applications.Key words: baffles, hydrodynamic damping, sloshing, tanks.

Three-Dimensional Analysis of Closed-Die Forging Processes: Part 1: Formulation

1989 ◽  
Vol 203 (1) ◽  
pp. 33-37 ◽  
Author(s):  
C F Lugora ◽  
A N Bramley
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Metal Flow ◽  
Three Dimensional ◽  
Total Rate ◽  
Die Forging ◽  
Closed Die Forging ◽  
Proposed Model ◽  
Optimum Velocity ◽  
Forging Load

In this series of papers, a theoretical model based on the upper bound elemental technique is presented for prediction of forging load and metal flow in three-dimensional closed-die forging processes. Three basic elements are introduced in order to partition a forging into simple elementary regions. An optimum velocity distribution within the forging is obtained by minimizing the total rate of energy dissipation using a simplex optimizing procedure. Applications of the proposed model are discussed in Part 2.

Mesoscale Dynamic Ice Formation and Breaking on a Vibrating Thin Membrane

1999 ◽  
Author(s):  
Jeff Fullilove ◽  
Norman Miller ◽  
Mark Shannon ◽  
Michael Philpot ◽  
Alexander Vakakis ◽  
...  
Keyword(s):  
Average Rate ◽  
Ice Formation ◽  
Experimental Measurements ◽  
Thin Membrane ◽  
Laser Vibrometry ◽  
Membrane Interaction ◽  
Analytical Results ◽  
Vibrating Membrane

Abstract We study dynamic ice formation and breaking (IF/B) on a thin vibrating membrane. The complicated discontinuous dynamics of the membrane is studied experimentally using laser vibrometry. Although the fluid- and coolant-membrane interaction with simultaneous ice forming and breaking is a complicated dynamical phenomenon, the average rate of ice formed and broken can be approximately quantified. The analytical results are compared to experimental measurements.

Comparative dynamic investigation of cross-laminated wooden panel systems: Shaking-table tests and analysis

2017 ◽  
Vol 21 (10) ◽  
pp. 1421-1436 ◽  
Author(s):  
Viktor Hristovski ◽  
Violeta Mircevska ◽  
Bruno Dujic ◽  
Mihail Garevski
Keyword(s):  
Energy Dissipation ◽  
Earthquake Engineering ◽  
Dynamic Properties ◽  
Seismic Energy ◽  
Experimental Tests ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Equivalent Viscous Damping ◽  
Cross Laminated Timber ◽  
Engineering Seismology

Cross-laminated timber has recently gained great popularity in earthquake-prone areas for construction of residential, administrative, and other types of buildings. At the Laboratory of the Institute of Earthquake Engineering and Engineering Seismology in Skopje, comparative full-scale shaking-table tests of cross-laminated timber panel systems have been carried out as a part of the full research program on the seismic behavior of these types of wooden systems, realized by Institute of Earthquake Engineering and Engineering Seismology, Skopje, and the Faculty of Civil and Geodetic Engineering (UL FCG), University of Ljubljana. Two different specimens built of cross-laminated timber panels have been tested: specimen containing a pair of single-unit principal wall elements (Specimen 1) and specimen containing a pair of two-unit principal wall elements (Specimen 2). In this article, the results from the shaking-table tests obtained for Specimen 2 and numerically verified by using appropriate finite element method–based computational model are discussed. Reference is also made to the comparative analysis of the test results obtained for both specimens. One of the most important aspects of the research has been the estimation of the seismic energy-dissipation ability of Specimen 1 and 2, via calculation of the equivalent viscous damping using the performed experimental tests. It is generally concluded that Specimen 2 exhibits a similar rocking behavior as Specimen 1, with similar energy-dissipation ability. Both specimens have manifested slightly different dynamic properties, mostly because Specimen 2 has been designed with one anchor more compared to Specimen 1. Forced vibration tests have been used for identification of the effective stiffness on the contacts for Specimen 2. This research is expected to be a contribution toward clarification of the behavior and practical design of cross-laminated timber panel systems subjected to earthquake loading.

Use of a stacked drop manhole for energy dissipation: a case study in Edmonton, Alberta

2009 ◽  
Vol 36 (6) ◽  
pp. 1037-1050 ◽  
Author(s):  
G. Adriana Camino ◽  
David Z. Zhu ◽  
Nallamuthu Rajaratnam ◽  
Manas Shome
Keyword(s):  
Energy Dissipation ◽  
Total Energy ◽  
Laboratory Investigation ◽  
Flow Regimes ◽  
Flow Patterns ◽  
The Other ◽  
Inflow Conditions ◽  
Water Depths ◽  
Total Energy Dissipation

This paper reports on a laboratory investigation into the performance of a novel stacked drop manhole design where two identical rectangular manholes are stacked one beside the other but at different heights so that there is a drop in elevation from one to the other. The focus of the study was to estimate the energy dissipation that occurs in such stacked manholes during diverse inflow conditions. Flow regimes inside the structure were identified and the effectiveness of the design was assessed under variable inflow conditions. Total energy dissipation in the stacked manhole was found to range from about 50% to 90%, and the contribution of each manhole chamber to the overall energy dissipation was assessed. A relationship between water depths in the manhole chambers and the corresponding outflow conditions was established. In addition, an analysis of the flow patterns and flow regimes highlighted the relevant parameters involved in the mechanisms of energy dissipation.

scholarly journals Estimating Energy Dissipation Rate from Breaking Waves Using Polarimetric SAR Images

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6540
Author(s):  
Rafael D. Viana ◽  
João A. Lorenzzetti ◽  
Jonas T. Carvalho ◽  
Ferdinando Nunziata
Keyword(s):  
Energy Dissipation ◽  
Total Energy ◽  
Dissipation Rate ◽  
Temporal Distribution ◽  
Wave Model ◽  
Breaking Waves ◽  
Fast Response ◽  
Energy Dissipation Rate ◽  
Sar Data ◽  
Total Energy Dissipation

The total energy dissipation rate on the ocean surface, ϵt (W m−2), provides a first-order estimation of the kinetic energy input rate at the ocean–atmosphere interface. Studies on the spatial and temporal distribution of the energy dissipation rate are important for the improvement of climate and wave models. Traditional oceanographic research normally uses remote measurements (airborne and platforms sensors) and in situ data acquisition to estimate ϵt; however, those methods cover small areas over time and are difficult to reproduce especially in the open oceans. Satellite remote sensing has proven the potential to estimate some parameters related to breaking waves on a synoptic scale, including the energy dissipation rate. In this paper, we use polarimetric Synthetic Aperture Radar (SAR) data to estimate ϵt under different wind and sea conditions. The used methodology consisted of decomposing the backscatter SAR return in terms of two contributions: a polarized contribution, associated with the fast response of the local wind (Bragg backscattering), and a non-polarized (NP) contribution, associated with wave breaking (Non-Bragg backscattering). Wind and wave parameters were estimated from the NP contribution and used to calculate ϵt from a parametric model dependent of these parameters. The results were analyzed using wave model outputs (WAVEWATCH III) and previous measurements documented in the literature. For the prevailing wind seas conditions, the ϵt estimated from pol-SAR data showed good agreement with dissipation associated with breaking waves when compared to numerical simulations. Under prevailing swell conditions, the total energy dissipation rate was higher than expected. The methodology adopted proved to be satisfactory to estimate the total energy dissipation rate for light to moderate wind conditions (winds below 10 m s−1), an environmental condition for which the current SAR polarimetric methods do not estimate ϵt properly.

AN EXPERIMENTAL STUDY OF A DIVERGENT NUCLEAR REACTOR

1953 ◽  
Vol 31 (2) ◽  
pp. 182-188 ◽  
Author(s):  
J. G. Bayly
Keyword(s):  
Experimental Study ◽  
Theoretical Model ◽  
Experimental Error ◽  
Nuclear Reactor ◽  
Relaxation Times ◽  
Experimental Measurements ◽  
Zero Energy

Experimental measurements of the relaxation times of a nuclear reactor were compared with the theoretical relaxation times in the range 1.6 to 186 sec. The work was done with the Chalk River Zero Energy Experimental Pile, ZEEP, in 1947, and showed that agreement within the experimental error could be obtained if the theoretical model used to represent the reactor was of the age-velocity type with a correction for the effect of the reflector.

scholarly journals Effects of temperature on performance of compressible magnetorheological fluid suspension systems

2017 ◽  
Vol 29 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Michael McKee ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Bulk Modulus ◽  
Temperature Effect ◽  
Magnetorheological Fluid ◽  
Suspension System ◽  
Shear Yield Stress ◽  
Temperature Dependent ◽  
Suspension Systems ◽  
Shear Yield

The temperature effect on performance of compressible magnetorheological fluid suspension systems is studied. Magnetorheological fluid is a temperature-dependent material where its compressibility and rheological properties change with temperature. Experimental studies were conducted to explore the temperature effects on the properties of the magnetorheological fluid and the compressible magnetorheological fluid suspension systems. The temperature effect on magnetorheological fluid properties included the bulk modulus, shear yield stress, and viscosity. It was found that the shear yield stress of the magnetorheological fluid remains unchanged within the testing range while both the plastic viscosity, using the Bingham plastic model, and the bulk modulus of the magnetorheological fluid decrease as the temperature of the fluid increases. A theoretical model that incorporates the temperature-dependent properties of magnetorheological fluid was developed to predict behavior of a compressible magnetorheological fluid suspension system. An experimental study was conducted using an annular flow compressible magnetorheological fluid suspension system with varying temperatures, motion frequencies, and magnetic fields. The experimental results are used to verify the theoretical model. Moreover, the stiffness and energy dissipation of the compressible magnetorheological fluid suspension system were obtained, experimentally. The effects of the temperature on performance characteristics of the compressible magnetorheological fluid suspension system were analyzed. It was found that both the stiffness and the energy dissipation decrease with an increase in the temperature of magnetorheological fluid.

THE ENERGY AND CENTRALITY DEPENDENCES OF THE PSEUDORAPIDITY DISTRIBUTIONS OF THE CHARGED PARTICLES IN Au+Au COLLISIONS

2012 ◽  
Vol 21 (01) ◽  
pp. 1250002 ◽  
Author(s):  
ZHIJIN JIANG ◽  
YUFEN SUN ◽  
QINGGUANG LI
Keyword(s):  
Theoretical Model ◽  
Impact Parameter ◽  
Beam Energy ◽  
Charged Particles ◽  
Nucleon Nucleon ◽  
Experimental Measurements ◽  
Phobos Collaboration ◽  
Free Parameters ◽  
Pseudorapidity Distributions ◽  
Theoretical Results

We present the pseudorapidity distributions of the charged particles in nucleus–nucleus collisions as the function of beam energy and impact parameter through weighted superposition of the pseudorapidity distributions in the effective binary nucleon–nucleon collisions. We then analyze with the theoretical model the experimental measurements carried out by BNL-RHIC-PHOBOS Collaboration in Au + Au collisions at [Formula: see text], 130, 62.4 and 19.6 GeV. The model has only two free parameters and the theoretical results favor the experimental measurements well.

A turbulent bore on a beach

1984 ◽  
Vol 148 ◽  
pp. 73-96 ◽  
Author(s):  
I. A. Svendsen ◽  
P. A. Madsen
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Shallow Water ◽  
Shallow Water Equations ◽  
Present Model ◽  
Finite Amplitude ◽  
Shear Stresses ◽  
Flow Conditions ◽  
Physical Conditions ◽  
Turbulent Bore

A theoretical model is developed giving a moderately detailed description of the flow in a turbulent bore, the velocity profiles, the shear stresses, the energy dissipation, etc. An analysis of the flow conditions at the toe of the turbulent front indicates significant differences from the usual description based on the finite-amplitude shallow-water equations, and it is shown that the present model gives a closer description of the actual physical conditions. Finally, numerical results are presented that illustrate how the model works, and test its validity on an example with known properties.

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