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a80da1a489
The outletPhaseMeanVelocity and waveVelocity boundary conditions now
support a "ramp" keyword, for which a function can be supplied to
gradually increase the input velocity. The following is an example
specification for an outlet patch:
outlet
{
type outletPhaseMeanVelocity;
Umean 2;
ramp
{
type quarterSineRamp;
start 0;
duration 5;
}
alpha alpha.water;
}
There is also a new velocityRamping function object, which provides a
matching force within the volume of the domain, so that the entire flow
is smoothly accelerated up to the operating condition. An example
specification is as follows:
velocityRamping
{
type velocityRamping;
active on;
selectionMode all;
U U;
velocity (-2 0 0);
ramp
{
type quarterSineRamp;
start 0;
duration 5;
}
}
These additions have been designed to facilitate a smoother startup of
ship simulations by avoiding the slamming transients associated with
initialising a uniform velocity field.
This work was supported by Jan Kaufmann and Jan Oberhagemann at DNV GL.