The present work is part of a research effort aimed at integrating a detailed model of airflow in large spaces with an algebraic multizone infiltration model to describe pollutant transport and coupled air flows within and between complex buildings and large spaces. In the past 15 years, zonal models were developed with the goal to obtain an approximate prediction of airflow characteristics in ...

The use of RANS models in the analysis of the urban climate and in air quality studies has become increasingly popular when predictions have to deal with complex flows, such as those arising at the street-scale. The need for model assessment and validation has thus also become crucial towards establishing the reliability of RANS simulations of heat and mass transport in urban areas. In this res...

The results of a series of numerical simulations for the NASA low-speed centrifugal compressor are presented. Large-eddy simulation (LES) is carried out together with the most commonly used Reynoldsaveraged Navier–Stokes (RANS) models, including the mixing length, k– and k– models. Predictions are compared with the available experimental data. It is seen that quantitative predictions of LES are...

Large Eddy Simulation (LES) is an effective intermediate approach between DNS and RANS, capable of simulating flow features which cannot be handled with RANS such as significant flow unsteadiness and strong vortex-acoustic couplings, and providing higher accuracy than RANS at reasonable cost but still typically an order of magnitude more expensive. Desirable modeling choices involve selecting a...

The actuator disc-RANS model has widely been used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large-scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and...

The paper evaluates a new method to prescribe synthesized turbulent inlet boundary conditions. The method can also be used when prescribing turbulent fluctuations at an interface between (U)RANS and LES regions when the flow enters the LES region. When making LES, DES or hybrid LES-RANS a precursor channel DNS is often used. The disadvantage of this method is that it is difficult to re-scale th...

A set of two phase flow experiments for conditions ranging from bubbly flow to cap/slug flow have been performed under isothermal concurrent air-water flow conditions in a vertical column of 3 m height. Also the liquid properties like the surface tension have varied by adding small quantities of 1-Butanol in order to see how these changes affect to the two phase flow properties. Numerical simul...

This research adopts the quasi three-dimensional hydraulic design method for the impeller of high specific speed mixed-flow pump to achieve the purpose of verifying the hydraulic design method and improving hydraulic performance. Based on the two families of stream surface theory, the direct problem is completed when the meridional flow field of impeller is obtained by employing iterative calcu...