ABSTRACT
The present chapter has been prepared to describe and discuss the problems associated with the formulation of the equations appropriate to the airflow distribution indoors, in terms of the governing conservation equations and turbulence modeling assumptions and the computational procedure required to solve the equations with boundary and inlet conditions. The elliptic partial differential equations, which govern the transport of mass, momentum, and energy, in addition to their derivations, are presented later; they are restricted here to steady and three-dimensional configurations where recirculation may occur, such as in the airflow in the air-conditioned applications. These time-averaged equations contain, for turbulent flows, second-order correlations of fluctuating properties, and models to determine these correlations are necessary to make the equations soluble. The governing differential equations, expressed in finite difference form, are solved numerically by an iterative procedure, which is described in detail later. The turbulence models embodied in the numerical computational techniques to represent these unknown correlations are discussed and the appropriate modifications suggested. The selected turbulence model, in the form of a set of steady partial differential equations, allows the predictions of the aerodynamics properties of the flow. The various assumptions, limitations, and required convergence criteria to satisfy the conservation equations are also discussed later.
