Schematic of the coordinate system used. Direction of motion of the cylinder is in the direction.
Prescribed velocity to the cylinder as a function of time. Shown for the case and .
Contours of vorticity and dilatation shown for , , and . Both are nondimensionalized by : (a) , (b) , (c) , and (d) . Vorticity contours in color from −1 (blue) to 1 (red) in steps of 0.02. Dilatation (negative in solid line and positive in dotted line) plotted from −0.1 to 0.1 in steps of 0.025.
Stream traces behind the cylinder at various Reynolds numbers. (a) Bulging of stream traces shown for case B. , , and . (b) Formation of an isolated vortex, the same case as in (a) and . (c) Vortex structure for case C: , , and . (d) Vortex structure for case D: , , and .
Variation of streamwise velocity along the axis of motion on the rear side at various time instants. Solid line: present calculation; symbols: experimental data of Bouard and Coutanceau (Ref. 14): (△) , (○) , and . (a) for , , and . (b) for , , and .
Evolution of drag coefficients with time for different values of but fixed and . Total drag: solid line; pressure drag: dashed line; viscous drag: dashed dotted line. (a) (b) .
Variation of peak pressure drag and peak total drag . (a) Variation with for , . Total drag: -△- ; pressure drag: -○-. (b) Variation with for and . Total drag: -△-; pressure drag: -○-. (c) Variation of total drag with . , : -△-; , : -◻-; and , : . Total drag for , : . Dotted line: Reference line with slopes 1 and 2.
Wall vorticity at different time instants for , , and . : dotted line; : dashed line; : -△-; : dashed dotted line; : -◻-; and : solid line.
(a) Normal pressure gradient at the wall at different time instants; (b) Tangential pressure gradient at the wall at different time instants. Legend: the same as in Fig. 8.
Comparison of wall vorticity for different at different time instants. , , and : dotted line; , , and : dashed line; , , and : solid line; , , and : dashed dotted line. (a) at and (b) at .
Contours of density, , plotted between −0.1 and 0.1 are shown in column (i). Contours of energy components, , , and plotted between and 0.03 are shown in columns (ii)–(iv), respectively. Row (a) corresponds to , (b) to , and (c) to . Shown for case , , and .
(a) Energy budget implied by time integrated form of Eq. (9) is shown for cases with , , (upper curve) and 3000 (lower curve). : solid line; other terms in Eq. (9): dashed dotted line. (b) Evolution of acoustic and entropy energy fluxes with time is shown for , , and two values of . for : solid line; for : dashed line; for : -△-; for : -◻-. (c) Evolution of kinetic , potential , and entropy energies with time is shown for , , and two values of . for : solid line; for : dashed line; for : -△-; for : -◻-; for : dashed dotted line; for : dotted line. All calculations are shown for control surface location .
Variation of total acoustic energy, , in the far-field. (a) Variation with for and . (b) Variation with for , (lower curve) and 0.3 (upper curve). (c) Scaling with . , : -○-; , : -◻-; , : -△-; , : -◁-; , : dashed dotted line with circles. Dotted line: Reference lines of slope 2 and 4.
Energy balance shown for control surface location . Legend: the same as in Figs. 12(b) and 12(c). (a) Surface integral terms. (b) Volume integral terms.
Mesh parameters for conditions of the simulations presented.
Article metrics loading...
Full text loading...