Mechanical Engineering - Research Publications
Permanent URI for this collection
Search Results
1 - 6 of 6
-
ItemStructure Inclination Angles in the Convective Atmospheric Surface Layer(SPRINGER, 2013-04)
-
Item
-
ItemSpatial averaging of velocity measurements in wall-bounded turbulence: single hot-wires(IOP Publishing Ltd, 2013-11)
-
ItemSpatial averaging of streamwise and spanwise velocity measurements in wall-bounded turbulence using ν- and x-probes(IOP PUBLISHING LTD, 2013-11)
-
ItemThe quiescent core of turbulent channel flow(CAMBRIDGE UNIV PRESS, 2014-07)Abstract The identification of uniform momentum zones in wall-turbulence, introduced by Adrian, Meinhart & Tomkins (J. Fluid Mech., vol. 422, 2000, pp. 1–54) has been applied to turbulent channel flow, revealing a large ‘core’ region having high and uniform velocity magnitude. Examination of the core reveals that it is a region of relatively weak turbulence levels. For channel flow in the range $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}Re_{\tau } = 1000\text {--}4000$, it was found that the ‘core’ is identifiable by regions bounded by the continuous isocontour lines of the streamwise velocity at $0.95U_{CL}$ (95 % of the centreline velocity). A detailed investigation into the properties of the core has revealed it has a large-scale oscillation which is predominantly anti-symmetric with respect to the channel centreline as it moves through the channel, and there is a distinct jump in turbulence statistics as the core boundary is crossed. It is concluded that the edge of the core demarcates a shear layer of relatively intense vorticity such that the interior of the core contains weakly varying, very low-level turbulence (relative to the flow closer to the wall). Although channel flows are generally referred to as ‘fully turbulent’, these findings suggest there exists a relatively large and ‘quiescent’ core region with a boundary qualitatively similar to the turbulent/non-turbulent interface of boundary layers, jets and wakes.
-
ItemNo Preview AvailableNumerical investigation of the behaviour of wall shear stress in three-dimensional pulsatile stenotic flows(Australasian Fluid Mechanics Society (AFMS), 2014)