Turbulent mixing is important in a wide variety of applications. One such application is high speed air breathing aircraft engines (supersonic combustion/hypersonic aircrafts). As aircrafts continue to fly at higher speeds, complete mixing has to be achieved within shorter combustion chambers to minimize fuel consumption, avoid combustion instabilities and decrease emissions. The turbulent mixing of two streams of gases (propane and air) is modeled in this tutorial.
Turbulent mixing is important in a wide variety of applications. One
such application is high speed air breathing aircraft engines
(supersonic combustion/hypersonic aircrafts). As aircrafts continue to
fly at higher speeds, complete mixing has to be achieved within shorter
combustion chambers to minimize fuel consumption, avoid combustion
instabilities and decrease emissions. The turbulent mixing of two
streams of gases (propane and air) is modeled in this tutorial.
This tutorial presents an analysis of a cross-flow phenomenon of a small pipe intersecting a large
pipe, which is typical of plumbing applications. The geometry is based on a CAD model that is directly
imported in CADalyzer. After defining the correct flow computational domain, appropriate inlet and
outlet boundary conditions will be prescribed. The location of the maximum velocity resulting from
this cross-flow will be identified, and flow streamlines from the small pipe into the large pipe will
be plotted.
In this tutorial, a pitching airfoil
is modeled. The airfoil oscillates in a sinusoidal fashion in the freestream. Two
grid systems are employed namely, the airfoil and the background grid system. A prescribed motion model is
employed to create the airfoil grid motion in the stationary background grid. The
moving airfoil grid and the stationary background grid communicate using
chimera methodology. The solution is carried out in two steps. First a steady
state solution is obtained with stationary airfoil. Next, the moving grid
simulation is carried out using the steady state solution as initial
condition.
This unsteady simulation involves a moving body and demonstrates the useof chimera and 6-DOF modeling features in CFD-FASTRAN. The flow has a free stream Mach number of 2.0 at AOA of 5 deg. The free-stream temperature and pressure are 101325Pa and 288.16K, respectively. The simulation includes two separate 6DOF motion models. 6DOF model # 1 governs the motion of the second stage (payload vehicle), and 6DOFmodel # 2 governs the motion of the first stage (booster vehicle). The payload vehicle has a rocket nozzle that is modeled with a time dependent inlet condition simulating rocket ignition. First a steady-state solution of the combined vehicle flying at 5 deg. angle of attack is obtained. Then at time t=0, the rocket motor ignites and pressure builds up between the stages resulting in the separation of the two vehicles. The thrust integration option is employed to account for the thrust component at the nozzle chamber.
User subroutines are built as Dynamic Link Libraries (DLL files for Windows) or
shared objects (.so files for UNIX platforms). The shared libraries are then
linked with CFD-ACE-SOLVER such that a two way communication between the
solver and the user defined input is established. In this tutorial, a custom Parabolic Velocity Profile is specified using the user subroutine UBOUND. This routine is called on a face by face basis for each bc record.
