The paper presents the results of an experimental and numerical study of the structure of a plume formed over a heated disk under conditions of conjugate heat transfer in a wide range of Grashof number. The data on the temperature field in the plume is compared with the visualization patterns. Numerical simulation was performed using the Ansys Fluent code, where the problem of the flow of a compressible gas in conditions of conjugate heat transfer in an unsteady formulation was solved under the assumption of laminar flow regime. As a result of a comparison of the results of physical and numerical experiments, there is a conclusion about a good qualitative concurrence of the flow structure. The heat transfer characteristics were studied experimentally and numerically: the local heat transfer coefficient, the heat flow from the heated disk, and the local and average Nusselt numbers. It is shown that the establishment of a periodic flow regime leads to a violation of the monotonicity of the distribution of the local heat transfer coefficient. In general, the data is in satisfactory agreement with the results of known works.