The flow in a gas turbine afterburner is highly complex since it is three dimensional and turbulent with major design requirements depending to a greater extent on the internal aerodynamics. The aim of this work is to carry out flow field analysis in an isothermal model of an afterburner using a computational fluid dynamics method. The calculations are performed using SIMPLE (Semi Implicit Method for Pressure Linked Equations) based algorithm with unstructured grid arrangement. The standard k-μ model is used for turbulence modeling. The three-dimensional velocities and turbulent kinetic energy have been predicted for the model afterburner and the flow field predictions agree satisfactorily well with the measurements. The velocity vector plots drawn along different longitudinal and cross sectional planes provide a wealth of information for different representative cases of afterburners. This will be helpful in understanding and estimating the multitude of parameters used in the afterburner design. The package used for the flow is FLUENT. This computer code is concerned with the numerical simulation of fluid flow, heat transfer, combustion and related phenomenon, which occur in engineering equipment and processes. Fluent code has a preprocessor, a solver and a post processor. It has capabilities for incorporating various turbulence models such as standard k-μ model, RNG model etc. In view of the close agreement between the predicted and experimental results it can be concluded that the present study can be effectively utilized in optimizing the design of aircraft afterburners. Copyright © 2001 Society of Automotive Engineers, Inc.