<abstract> <p>The current study is based on the mechanism of mixed convection and solar thermal radiation in Walters'-B fluid considering tera-hybrid nano-structures using convective boundary constraints (CBC) and (CHF) constant heat flux. The heat transmission phenomenon of the current study is taken into account under the influence of triple-suspended nanoparticles. The current problem has several potential applications, including improvements in solar thermal energy systems, nanofluids, aerospace, cooling processes, automotive engineering, and numerical modeling methods. A numerical approach, namely Crank-Nicolson, is utilized in the modeling of 3D Walter's B fluid past over a 3D circular cylinder whose radius varies sinusoidally for evaluation of velocity and temperature distributions. For mathematical modeling, the Cartesian coordinate system was used for the current study. Comparative analysis between constant heat flux (CHF) and convective boundary constraints (CBC) was demonstrated graphically against multifarious parameters towards the temperature profile and velocity profiles along the x-axis and in the y-axis. Moreover, comparative analysis for dissimilar parameters was manifested for Nusselt number through tables, and graphically for skin friction co-efficient and Nusselt number and has shown excellent accuracy. It was estimated that by enhancing values of <italic>Q<sub>sr</sub></italic>, <italic>C</italic>, <italic>H<sub>s</sub></italic> and <italic>E<sub>c</sub></italic>, it was addressed that temperature curve increases for CHF and CBC cases.</p> </abstract>