Flow over macroscopic hexagonal structured surfaces. Experimental Investigation : Grin Verlag : 9783346610157 : 3346610152 : 02 May 2022 : Doctoral Thesis / Dissertation from the year 2014 in the subject Engineering - Mechanical Engineering, grade: 1,3, Brandenburg Technical University Cottbus, language: English, abstract: The flow over macroscopic patterned/structured surfaces was investigated in a subsonic wind tunnel over Reynolds numbers ranging from 3.14 x 104 to 2.77 x 105 for cylinders and from 5.34 x 105 to 11.27 x 106 for plates. The investigations were accomplished by measuring local and global drag, velocity profiles and by visualization of the flow above the surface. Flow visualization was carried out by using oil-film technique and velocity profile measurements to elucidate the observed effect, and hence present the mechanism responsible for theobserved drag reduction. Investigations on structured plates were performed with the help of hot wire anemometry and oil film inte