Hello, all. When i have flow rate fixed in U, i get a flow direction in or out of a patch (depending on whether it is an inlet or outlet) and it is not necessarily normal. How do i achieve this with an expr if i want to calculate a custom flow rate. I tried exprFixedValue and it has face() which is face normal. Does it have any similar function for a flow direction that it would choose if i used a flow rate bc without expr? This is openfoam 2204 or something like that (openfoamcom,not openfoamorg)