Search results for "FD"
showing 10 items of 483 documents
Channel Estimation and Interference Cancellation for MIMO-OFDM Systems
2007
This paper proposes a new channel estimation method and a new interference cancellation scheme for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems in the presence of intersymbol interference (IS1). The proposed channel estimation method uses special training sequences (TSs) to have a desirable crest-factor of the transmitted training signal, and to prevent the influence of ISI on the channel estimation performance. By using the recommended training sequences, the ill-conditioned problem of the least square (LS) filter integrated in the proposed channel estimator can be avoided. The proposed interference cancellation scheme uses the estimated cha…
Modelling and Simulation of Gas–liquid Hydrodynamics in a Rectangular Air-lift Reactor
2013
Abstract Computational Fluid Dynamics is a quite well established tool for carrying out realistic simulations of process apparatuses. However, as a difference from single phase systems, for multiphase systems the development of CFD models is still in progress. Among the two-phase systems, gas–liquid systems are characterised by an additional complexity level, related to the fact that bubble sizes are not known in advance, being rather the result of formation and breakage-coalescence dynamics and therefore of complex phenomena related to flow dynamics and interfacial effects. In the present work, Euler–Euler Reynolds-averaged flow simulations of an air-lift reactor are reported. All bubbles …
A numerical solution that determines the temperature field inside phase change materials: application in buildings
2013
The use of novel building materials that contain active thermal components would be a major advancement in achieving significant heating and cooling energy savings. In the last 40 years, Phase Change Materials or PCMs have been tested as thermal mass components in buildings, and most studies have found that PCMs enhance the building energy performance. The use of PCMs as an energy storage device is due to their relatively high fusion latent heat; during the melting and/or solidification phase, a PCM is capable of storing or releasing a large amount of energy. PCMs in a wall layer store solar energy during the warmer hours of the day and release it during the night, thereby decreasing and sh…
Computational Modeling of Ascending Thoracic Aortic Aneurysm and Dissection
CFD prediction of bubbles local gas hold-up in 2-dimensional gas-solid fluidized beds
2008
Tirdzniecības stratēģija un tās pielietošana CFD valūtas tirdzniecībā
2021
Darba autora iepriekšējā pieredze, nodarbojoties ar CFD instrumentiem, rāda, ka reālas iespējas nopelnīt ir, lai gan jāuzsver, ka peļņa pārsvarā ir gūta īstermiņā, ilgtermiņā, tomēr, rezultāti ir bijuši negatīvi. Galvenais trūkums kurš ir konstatēts, ir tas, ka trūkst stratēģiski pārdomātas rīcības tirdzniecības darījumos, kurš balstītos uz konkrētām darbībām, spētu dot sagaidāmus rezultātus no tirdzniecības ilgtermiņā. Negatīvā pieredze lika autoram aizdomāties par stratēģijas nozīmīgumu tirdzniecības darījumu veikšanā un nepieciešamību pētīt tirdzniecības stratēģiju izveides principus. Darba mērķis: pamatojoties uz teorētiskām atziņām par tirdzniecības stratēģijas izveidi izstrādāt un apr…
Study of the performances of a fluidynamic actuator
2018
Aim of this paper is presented a new methodology to study how different geometric parameters affect the performance of a hydraulic actuator. Preliminarily, the real working conditions of a hydraulic machine have been simulated by means of a CFD module. After, to test the reliability of the simulations, the obtained numerical results have been compared with the experimental data of a real prototype. This comparison demonstrates a good level of agreement between numerical and experimental results. Different simulations have been setup by modifying the actuator geometry and evaluating the efficiency of every analysed configuration. The results of this study give useful guidelines for the choic…
CFD simulation of solid-liquid suspension startup in a stirred tank
2008
Top-covered unbaffled stirred tanks: experiments and numerical simulations
2015
In this work computational fluid dynamics was employed to predict the flow field of an unbaffled stirred tank from steady to turbulent conditions