air flow

This paper investigates, using CFD simulation, the influence on energy and comfort of the position of small openings for air exchange between rooms in ventilated and air-conditioned rooms of highly airtight houses. Measurements of velocities and temperatures were operated in a Japanese house with floor heating and central air conditioning system providing some fresh airl. Results agree with these of CFD calculations. Calculations were used to search for the optimal position of small ventilation openings between rooms.

This paper presents a survey on methods of measuring airflow, especially methods using inlet nozzles. Methods are compared with respect to uncertainties due to nozzle shape and/or measurement, handling friendliness, and economics. Authors describe a new nozzle contour with a constant air velocity along its surface. They explain advantages and disadvantages of this new design.

In general, there are 3 locations used for the fresh air supply in a standard cleanroom : under the ceiling of supply air plenum, at the return air shaft, and under the raised floor. In this study, the influences of the three different fresh air supply locations on field velocity and temperature distributions of fan filter unit are investigated then compared. The airflow distribution is simulated by the standard k-e turbulence model. Results are presented and discussed..

This paper deals with a computer simulation of airflow and indoor environment in livestock buildings. Simulation results have been analysed and visualized with a Virtual reality visualization . The definition of virtual reality is given first , then the presentation of the 3 Virtual reality systems possibly used for the visualization, and finally a simulation tool.
5 cases were selected to demonstrate the different simulation and visualisation possibilities for people form the industry.

In so far as a CFD analysis is becoming more and more complex. The presentation of the results must be adapted according to the audience. This paper gives first different methods of analysis and an overview of different levels for the presentation of CFD results. Examples of complex flow visualizations illustrate that paper.

This paper deals with the effect of discharging the air from a diffuser elevated above the floor. The temperatures have been measured and the airflow patterns visualised close to a diffuser for displacement ventilation, results from the whole-field method (using infrared thermography) were images of different colours representing different temperatures of the air close to the diffuser.. The aim of the measurements was to see how the elevations of the diffuser above floor level and the thermal jet length of the supply could affect the near zone.

This paper is built on the hypothesis that, as the heated area increases from a point source, a displacement flow is maintained until the heated area reaches a critical fraction of the floor area, after which there is a transition to mixing flow.This hypothesis is tested in a series of laboratory experiments with the investigation of thermal stratification and flow patterns produced by a range of area heat sources located on the floor of a naturally ventilated enclosure.

This paper develops a simple analytical model for the air flow inside a room with different discrete heating and cooling sources, established by combined localised and distributed heat input. Results from experiments are compared to simple theoretical models of the flow pattern.

CFD and fluid net models used for natural ventilation designs do not consider the impacts of fluctuating characteristics to the mean airflow rate. This paper presents first a correctional method for predicting mean airflow rate of natural ventilation when the average wind velocity is more important than velocity fluctuation. A correctional coefficient for airflow resistance of multi-zone models is deduced. This method is then applied to a big atrium of a naturally ventilated five floor laboratory.

A large opening has first been defined as "an opening where the flow is not fully unidirectional". Then an experimental setup has been installed to conduct wind tunnel measurements on several models of a circular disk, in order to characterize the pressure distribution on simple objects provided both with and without openings.