Numerical investigation of the effect of roughness on convective heat transfer under stationary laminar flow of M20 oil around a circular cylinder

Convective heat transfer under the laminar flow $(\text{Re} = 60)$ of M20 oil and air heated to $333$ K around a circular cylinder with a wavy surface roughness is computed using multiblock computational technologies, which are implemented in package VP2/3 for solving the Navier–Stokes and energy equations as part of the procedure for adjusting pressure. It is shown that at a roughness depth of $1\%$ in fractions of the cylinder diameter, the heat transfer from the surface in oil increases by $21\%$, and the thermal–hydraulic performance grows by $17\%$.