This paper investigated the change in the thermal and structural characteristics of turbulent spot footprints, affected by Reynolds number, jet velocity and duration using thermochromic liquid crystals. The turbulent spot was induced on an isothermal plate by a small pulsating water jet through a 1 mm diameter hole in an upward direction across the mainstream flow, having velocities of 0.128, 0.160, and 0.192 m/s. The jet was set to Reynolds number values of 3300, 5500, 7700, 9900, 13,100, and 16,400 and dimensionless injecting durations of 0.5, 0.7, 0.9, 4.7, 9.5, 23.6 and 47.3. The results showed that the Re of the jet strongly affected on the characteristics of the turbulent spot. The Nu increased approximately 14% when the injecting duration changed from 4.7 to 47.3 while the epsilon(s)/tau(inj) decreased by 12 times. The spot area, the heat transfer area, the velocity of the spot leading edge, the half spreading angle, and the non-dimensional spot propagation parameters increased approximately 75, 60, 3, 70, and 85%, respectively, but the velocity of the spot trailing edge decreased about 20% at tau = 260. Meanwhile, the variation of jet velocity caused a different shape of disturbance. Furthermore, the predictive formulas for the Nusselt number of the turbulent spot, induced from the injecting duration between 4.7 and 47.3, were also provided and the mechanism of the flow and heat transfer discussed. (C) 2019 Elsevier Ltd. All rights reserved.