Computational Fluid Dynamics

Iowa State University's Mechanical Engineering Department has been a leader in Computational Fluid Mechanics for over two decades. Formal graduate coursework has been offered in the subject since 1972. This early teaching activity stimulated the development of one of the first engineering textbooks on the subject. In 1980 NASA designated Iowa State University (ISU) and four other universities as centers of excellence in Computational Fluid Dynamics (CFD) and provided funding over three and one-half years to expand educational activities in CFD. With this funding, a Computational Fluid Dynamics Center was formed at ISU to coordinate and promote interdisciplinary activities in this subject area. At present, 10 faculty members and 38 graduate students in the departments of Aerospace Engineering and Engineering Mechanics, Chemical Engineering, and Mechanical Engineering participate in educational and research activities coordinated by the CFD Center.

Computational fluid mechanics is a relatively new area of specialization. The discipline deals with the numerical simulation of flow by solving the governing conservation equations--usually in partial differential form--numerically on a high-speed digital computer. In recent years the trend has been toward greater reliance on computer simulations for supplying the information needed in the design of engineering devices. This trend can be largely explained by economics. Over the years, computer speed has increased much more rapidly than computer costs. The net effect has been a significant decrease in the cost of performing a given calculation; in fact, the reduction has been at least a factor of 10 every 8 years. On the other hand, the costs of performing experiments have been steadily increasing in recent years due to the general inflation rate, the rising cost of energy required to power experimental facilities, and the increasingly severe operating conditions found in recent applications.

In addition to economics, computer predictions offer other important advantages. Once a computer algorithm has been developed, a computational study can be performed with remarkable speed, often allowing the designer to study the implications of many different configurations in less than a day to choose the optimal design. The corresponding experimental investigation is likely to take a very long time. In addition, a computer solution to a problem gives detailed information. It can provide values of all the relevant variables throughout the domain of interest, including quantities that are difficult or impossible to measure experimentally. Naturally, it's important to make as many comparisons of the numerical predictions with experimental data as possible in order to establish the validity of the numerical formulation.

Current projects (application areas denoted by information in parentheses) in Computational Fluid Dynamics include:
the numerical prediction of stagnation region heat transfer in unsteady flow fields (gas turbine engines)
numerical simulation of liquid sloshing in spin-stabilized satellites (many space applications, ship hydrodynamics, transportation of liquids)
numerical modeling of turbulent jets in a cross flow (vertical and short take-off and landing aircraft)
a velocity-vorticity method for computing three-dimensional inviscid flows in complex geometries with applications to the launch configuration of the space shuttle (general complex geometries arising in aerodynamic applications including flow about complete aircraft)
a primitive variable, strongly implicit calculation procedure for viscous flows at all speeds (a general Navier-Stokes solution technique for unsteady two- and three-dimensional flows)
an unsteady boundary-layer numerical method for internal and external flows with applications to fortification schemes for the Navier-Stokes equations (turbomachinery, heat exchangers, flows in propulsion systems)
simulation of internal viscous flows using unstructured grids (turbomachinery).