Computational fluid dynamics was born principally in the aerospace field as a method for fluid flow and heat transfer research methods following experimental and analytical approaches. Along with progress in the cost performance of computers, computational fluid dynamics is now establishing itself as a tool to improve production processes and product quality in the steel, nonferrous metals, glass, plastics, and composite materials industries.

Materials manufacturers use computational fluid dynamics for diverse purposes:

• 1. Reduction in experimental conditions and costs;

• 2. Detailed analysis of mechanisms with multifaceted information unobtainable through experimentation;

• 3. Universal tool for scale-up; and

• 4. Evaluation of novel processes.

It can be readily imagined that accuracy, flexibility, and other requirements of computational fluid dynamics should vary with specific applications.

Fluids generally observed in materials manufacturing processes are molten materials such as metal, glass, and plastics, and gases for stirring and refining. In the flow of such fluids, materials quality and process characteristics are governed by the following:

1. 1. Transport phenomena in the bulk region (where fluid flow is normally turbulent);

2. 2. Chemical reaction at interfaces;

3. 3. Transport phenomena in boundary layers near the interfaces; and

4. 4. Complex coupled phenomena (heat transfer, diffusion, chemical reaction, phase transformation like solidification, free surface, electromagnetic force, and bubble flow).