Search results for " kinetic energy"

Turbulent jet through porous obstructions under Coriolis effect: an experimental investigation

2021

AbstractThe present study has the main purpose to experimentally investigate a turbulent momentum jet issued in a basin affected by rotation and in presence of porous obstructions. The experiments were carried out at the Coriolis Platform at LEGI Grenoble (FR). A large and unique set of velocity data was obtained by means of a Particle Image Velocimetry measurement technique while varying the rotation rate of the tank and the density of the canopy. The main differences in jet behavior in various flow configurations were assessed in terms of mean flow, turbulent kinetic energy and jet spreading. The jet trajectory was also detected. The results prove that obstructions with increasing density…

Linking the Kinetic Energy Fraction and Equivalent Length Method for Trickle Irrigation Design under Local Losses

2020

New methods using analytical relationships to design drip irrigation laterals and subunits have been introduced in recent years based on the assumption that minor losses can be neglected. This assumption could be relaxed by applying the equivalent method, which makes it possible to account for minor losses, such as those caused by emitter connections, through formulas based on the rationale that an equivalent length of the drip lateral produces the same losses. However, equivalent length formulas are empirical; thus, they do not necessarily cover the entire range of conditions in the real-world contexts in which the formulas will be applied, and their extrapolation could lead to erroneous r…

Utility of Hovmöller diagrams to diagnose Rossby wave trains

2011

The study investigates and compares various methods that aim to diagnose Rossby wave trains with the help of Hovm¨ oller diagrams. Three groups of methods are distinguished: The first group contains trough-and-ridge Hovm¨ oller diagrams of the meridional wind; they provide full phase information, but differ in the method for latitudinal averaging or weighting. The second group aims to identify Rossby wave trains as a whole, discounting individual troughs and ridges. The third group contains diagnostics which focus on physical mechanisms during the different phases of a Rossby wave train life cycle; they include the analysis of eddy kinetic energy and methods for quantifying Rossby wave brea…

A numerical model of the cloud-topped planetary boundary-layer: Radiation, turbulence and spectral microphysics in marine stratus

1996

A numerical model of the cloud-topped planetary boundary-layer is presented. The model is one-dimensional with special emphasis on a detailed description of cloud microphysical processes. Aerosols and cloud droplets are treated in a two-dimensional particle-distribution whereby the activation of aerosols is calculated explicitly by solving the droplet-growth equation at all relative humidities. Atmospheric radiation is determined with a δ-two-stream radiation scheme. Turbulent fluxes are parametrized as a function of the turbulent kinetic energy. Numerical results are presented which are obtained by utilizing measurements made over the North Sea. The interaction between radiation, turbulenc…

Investigating marine shallow waters dynamics to explore the role of turbidity on ecological responses

2009

The ecological tangible effect of the complex interaction between sediments and water column in shallow waters is represented by turbidity which is a common feature of most aquatic ecosystems: it varies both temporally and spatially; it can cover a huge area and persist for a long period or it can be very localized and temporary. Among many factors able to generate turbidity, wind generated wave action and water mass movements due to tides seem important in causing resuspension of sediments. Although there is much research spent in last decades on this topic and many models to explain the complexity of the wind-water-sediment interaction, some interactive aspects are too site specific and t…

Surface to boundary layer coupling in the urban area of Lisbon comparing different urban canopy models in WRF

2019

Abstract This work presents a sensitivity study to evaluate different Urban Canopy Models (UCM) existing within the Weather Research and Forecasting Model (WRF) in the urban area of Lisbon, Portugal. Several hind-cast simulations were carried out for a selected period in July 2010, in which synoptic conditions favoured urban heat island formation. We aim to gain knowledge on the feedback of modified urban canopy representation in WRF on local scale meteorology and the boundary-layer dynamics over the urban area, by comparing a single layer urban canopy model (SLUCM) and a more sophisticated multi-layer building effect parametrisation (BEP). We find significant differences in the characteris…

Closure to “Analyzing Turbulence Intensity in Gravel Bed Channels” by F. G. Carollo, V. Ferro, and D. Termini

2008

Fuzzy logic approach to predict vehicle crash severity from acceleration data

2015

Vehicle crash is a complex behavior to be investigated as a challenging topic in terms of dynamical modeling. On this aim, fuzzy logic can be utilized to analyze the crash dynamics rapidly and simply. In this paper, the experimental data of the frontal crash is recorded using an accelerometer located at the centre of the gravity of the vehicle. The acceleration signal was the raw data from which the collision intensity expressed by the kinetic energy and the jerk were derived. The fuzzy logic model was then developed from the two inputs namely kinetic energy and jerk. The output variable is the crash severity expressed as the dynamic crash. The result shows that the jerk contributes much to…

Measuring Rainfall Kinetic Power in Two Sicilian Experimental Areas by Drop-Size Distribution Data

2023

The rainfall kinetic energy, which affects soil erosion processes, can be calculated by the drop-size distribution (DSD) and falling velocity. This study presents the outcomes derived by the DSDs recorded with the same optical disdrometer in two experimental areas, located in Sicily (southern Italy). Specifically, the DSDs were recorded from March 2017 to December 2019 at Sparacia and from June 2006 to April 2014 at Palermo. The aims of this paper are both to compare the DSDs for the two sites and to evaluate the applicability of Gamma theoretical distribution. Moreover, the relations of rainfall kinetic power vs. rainfall intensity are assessed. Differences in DSDs, especially for rainfall…

A Feasibility Analysis of an Electric KERS for Internal Combustion Engine Vehicles

2019

In this work, the authors evaluate the energetic and economic advantages connected to the implementation of an electric Kinetic Energy Recovery System (e-KERS) on an internal combustion engine vehicle (ICEV). The e-KERS proposed is based on the use of a supercapacitor (SC) as energy storage element, a brushless motor generator unit (MGU) for the conversion of the vehicle kinetic energy into electric energy (and vice versa), and a power converter properly designed to manage the power transfer between SC and MGU. The low complexity of the system proposed, the moderate volume and weight of the components selected for its assembly, together with their immediate availability on the market, make …