Characteristic features of hydrodynamics and heat transfer in transverse flow past cylinders with dimples in single-row bundles

The results of experimental investigation of heat transfer and characteristic features of the hydrodynamics in transverse air flow past single-row bundles of cylinders, the surface of which is made up of the systems of symmetric and asymmetric cylindrical dimples are presented. In the investigated range of Reynolds numbers from 3300 to 63,000, the maximum degree of heat transfer intensification in comparison with a smooth cylinder attains 1.78, whereas the hydraulic resistance of the bundle is increased by a value less than 14%. Some kinds of the investigated systems of dimples favor a decrease in the zone of reverse flows downstream of a cylinder by a factor of 2-4. The frequencies of sonic vibrations generated during flow past the dimples located near the front point of the cylinder are close to the frequencies appearing in flow past the same dimples located on a plane surface. The possibility of purposeful selection of the diameter of dimples for maximum reduction in the length of the zone of reverse flows behind cylinder is shown. © 2004 Begell House, Inc.