Methods and apparatus enable sensing flow of a fluid inside a conduit with an array of pressure or strain sensors. Inputs for a curve fit routine include power correlation values at one of multiple trial velocities or speeds of sound and several steps on either side utilizing data obtained from the sensors. The velocity at which a curve fit routine returns a max curvature result corresponds to an estimate value that facilitates identification of a speed of sound in the fluid and/or a velocity of the flow. Furthermore, a directional quality compensation factor may apply to outputs from the curve fit routine to additionally aid in determining the velocity of the flow.