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Results of an experimental study of a turbulent flow past a flat rib with different angles of alignment toward the flow and with different rib heights are presented. The angle of rib alignment toward the flow is varied within ϕ = 50-90 • . Vortex formation is visualized, and the coordinates of the reattachment line are determined. It is demonstrated that a decrease in the angle ϕ forms a reattachment region and makes the flow behind the rib more three-dimensional. Pressure coefficients are measured in different longitudinal sections of the channel behind the rib with a varied angle of rib alignment ϕ. Temperature fields on the surface behind the rib are measured by means of an infrared imager and by thermocouples, and the corresponding heat-transfer coefficients are calculated. The effect of the angle of rib alignment toward the flow and the rib height on dynamic and thermal characteristics of the separated flow is analyzed.Introduction. Heat transfer in channels of various devices used in power engineering is often intensified with the help of various obstacles, e.g., flat ribs. In a separated flow, both upstream and downstream of the rib, generation of large-scale vortex structures and interaction of coherent structures with the wall promote intensification of heat transfer on the wall. At the same time, the presence of obstacles leads to an undesirable increase in pressure losses. Thus, the task is to increase heat transfer and simultaneously reduce pressure losses. To solve this problem, one has to study the physical mechanisms of controlling vortex formation in separated flows and carefully measure the dynamic and thermal characteristics in a system of ribs and behind a single obstacle, in particular, behind a single rib.Separated turbulent flow behind a flat obstacle aligned at an angle to the flow has some specific features, as compared to the flow behind an obstacle placed perpendicular to the flow. One of such features is a significant amplification of heat transfer [1][2][3][4]. This phenomenon is more and more widely used in engineering, for instance, for effective cooling of turbine blades or for increasing heat output in heat exchangers. As the obstacle is aligned at an angle to the free stream, the flow is three-dimensional. Numerical calculations of three-dimensional separated turbulent flows require large computational resources and do not ensure a necessary accuracy. In modeling oblique flows, a question arises whether there are regions and directions with invariant values of both dynamic and thermal characteristics, which is particularly important in the case of a single obstacle.There are few papers that describe experimental investigations of the flow structure behind a single obstacle aligned at an angle to the flow, and there are even fewer papers where the thermal characteristics under these conditions are studied. Hancock and McCluskey [5] considered the flow behind a rib aligned at an angle ϕ = 65 • to the flow and compared the results with the data for ϕ = 90 • . The components of the me...

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