Simulation of the natural ventilation on scale model of a livestock house: Determination of airflow pattern in a water table

I. Mat Sharif

Abstract

A simulation study was conducted to determine the airflow patterns for a naturally ventilated livestock house. These studies were based on qualitative judgement using a visualization method to analyse the characteristics of the air flow through different parts of the house. The purpose was to determine the quality of air movement, air distribution and factors influencing them. These determinations of airflow pattern are of great importance in the design of an effective natural ventilation system. The experiment was conducted in a water table laboratory using two-dimensional 1:30 scale models of a typical livestock house in Malaysia. The results showed that the airflow had two distinct forms: the primary flow which is stable and the most dominant current and unstable secondary flow in circular motions near the floor and the roof. The primary current is the incoming airflow caused by a pressure difference between the inside and outside of the house. The secondary flow is induced from the primary flow due to obstructions that create high and low pressure areas inside the house. It was found that the height of the ridge between the main roof and ridge cover in the model showed no effect on airflow pattern and thus does not affect the ventilation rate.

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