In order to clarify vortex mechanisms under a turbulent flow field to explain enhanced biomass productivity, computational fluid dynamics and a miniature Doppler velocimeter were employed to investigate the promoted vorticity magnitude and turbulent kinetic energy to support the increased actual photochemical efficiency of Arthrospira platensis in a raceway pond with alternatively permutated conic baffles. Results showed that whereas the first two parameters increased by 5.9 and 13.9 times, respectively, the third rose on an average by 28% to the value of 0.59 measured on pulse-modulated fluorometer. Furthermore, it was detected on a Nikon inverted-fluorescence microscope that the average helix pitch and trichome length increased by 14% and 10% respectively, resulting in higher biomass productivity (34.8%).