# AcuTrace Command Reference Manual

Commands of AcuTrace, a particle tracer that runs as a post-processor to or a co-processor with AcuSolve.

AcuTrace computes particle traces as a series of segments using a fifth-order time-discontinuous Galerkin (TDG) method with error control for solving ordinary differential equations. AcuTrace solves the particle motion and stretch evolution equations. These can be augmented by one or more user defined evolution equations. It computes traces for unsteady as well as steady flow fields, for flows with mesh motion as well as without, and for flows computed on meshes with interface surfaces. AcuTrace can also compute traces for flows on meshes with multiple reference frames in two ways; by converting flow velocities to the local reference frame or by treating the boundaries between stationary and rotating reference frames as interface surfaces and the flow as pseudotransient.

To solve a problem with AcuTrace, you must first run AcuSolve. This can be done concurrently. You must also create a trace input file. Once these two steps are complete, AcuTrace is invoked with the command acuRunTrace. See the AcuSolve Programs Reference Manual for further details.

The trace input file consists of one or more commands, each having zero or more parameters. These commands define the problem parameters, such as solution strategies, initial conditions and output.

The command style for AcuTrace, command format, command qualifier usage, parameter format, parameter operators and functions, is identical to the style used by AcuSolve. For these details, see the AcuSolve Command Reference Manual.