An ultrasound system includes a 2-D transducer array and a velocity processor. The 2-D transducer array includes a first 1-D array of one or more rows of transducing elements configured to produce first ultrasound data. The 2-D transducer array further includes a second 1-D array of one or more columns of transducing elements configured to produce second ultrasound data. The first and second 1-D arrays are configured for row-column addressing. The velocity processor processes the first and the second ultrasound data, producing 3-D vector flow data. The 3-D vector flow data includes an axial component, a first lateral component transverse to the axial component, and a second lateral component transverse to the axial component and the first lateral component.