An apparatus (100) comprises at least one processor (110,210,530,550,385) and at least one memory (120,220) including computer program code. The memory (120,220) and the processor (110,210,530,550,385) are configured to, in respect of a ground-supported or liquid-supported body (401,411) travelling or to travel through a fluid, receive a determined magnitude and direction of a current within a forthcoming fluid zone (410,420), the magnitude and direction of the current determined from particulates suspended in the forthcoming fluid zone (410,420), and process the determined magnitude and direction of the current to provide for at least one of: a change in one or more fluid dynamical properties of the body (401,411), or navigation control of the body (401,411).