Experimental study of transient convective flows from a suddenly heated groove

•Transient convective flows from a groove with a bottom heated are investigated experimentally.•The evolution and property of transient convective flows are characterized.•The transition from periodic to chaotic flows is identified and discussed. Transient convective flows from a groove with a bottom suddenly heated are investigated using shadowgraph visualization and thermistor measurement. The evolution and property of transient convective flows are characterized. The scaling laws of the thickness of the thermal fluid layer and the velocity of the plume are validated by shadowgraph data. Shadowgraph visualization demonstrates that the plume may move along the groove, which was highlighted in the previous numerical study. In addition, temperature time series measured by thermistors are used to describe the oscillations of unsteady convective flows. The frequency of the oscillations in the fully developed stage is obtained using the spectral analysis. Further, the transition from periodic to chaotic flows is identified and discussed.