<p>The use of three-dimensional (3D) jet impact flow is crucial in various industries, particularly for the efficient cooling of turbomachinery and electronic components. This study investigates the thermal and flow characteristics of jets on 3D curved concave surfaces through experimental and numerical simulations. Experiments were conducted at a jet Reynolds number (Re) of 7000, using a nozzle diameter (<i>d</i>) of 5&#xa0;mm, with the nozzle-to-surface distance (<i>H</i>/<i>d</i>) set at 2 and 5. Instantaneous 3D temperature fields on a semicylindrical concave surface were measured using thermographic phosphor techniques. Based on experimental results for the radial distribution of the Nusselt number (Nu), the detached-eddy simulation model was selected for numerical simulations to further analyze heat transfer and flow mechanisms. Both experimental and simulation results revealed that the <i>H</i>/<i>d</i> significantly affect heat transfer characteristics. Notably, at lower <i>H</i>/d ratio (<i>H</i>/<i>d</i> = 2), secondary peaks in the Nu were observed near the stagnation region (1.4 &lt; <i>r</i>/<i>d</i> &lt; 2.5), attributed to vortex formation, flow separation, and reattachment. This research effectively captures the complex thermal dynamics on concave surfaces, enhancing the understanding of heat transfer and flow behavior when jets impact curved surfaces. The findings provide valuable insights for improving the thermal management performance of concave mechanical components.</p> Graphical abstract <p></p>