Ansys Employee

If you're perturbing the velocity the solution won't settle down, unless you're only doing it once. In which case you'll need the transient solver (with it's associated increase in time) until the flow stabilises (ie when the perturbation leaves the domain).

As you've not actually explained what you're trying to do we can't comment on which schemes to use. As the model is fairly small, I'd just run it: shouldn't take too long.