Topic
Pipe flow
About: Pipe flow is a research topic. Over the lifetime, 13826 publications have been published within this topic receiving 351605 citations.
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TL;DR: In this article, five methods of using narrowband liquid crystals for the measurement of local heat transfer coefficients are reviewed, including the heated-coating method, three variations of the transient method (preheated wall transient, duct-insertion technique, and shroud-heating technique), and a uniform coating method.
116 citations
TL;DR: In finite-Reynolds-number pipe flow, long-lived trains of particles aligned with the flow are observed located on the Segre–Silberberg equilibrium position which is an annulus close to the wall at the large Reynolds numbers investigated.
Abstract: In finite-Reynolds-number pipe flow, we have observed long-lived trains of particles aligned with the flow. These trains are located on the Segre–Silberberg equilibrium position which is an annulus close to the wall at the large Reynolds numbers investigated. The effect seems to be controlled by inertia and more precisely by the particle Reynolds number.
116 citations
TL;DR: In this article, an experimental investigation of laminar gas flow through microchannels is presented, where the independent variables: relative surface roughness, Knudsen number and Mach number were systematically varied to determine their influence on the friction factor.
Abstract: We present an experimental investigation of laminar gas flow through microchannels. The independent variables: relative surface roughness, Knudsen number and Mach number were systematically varied to determine their influence on the friction factor The microchannels were etched into silicon wafers, capped with glass, and have hydraulic diameters between 5 and 96 μm. The pressure was measured at seven locations along the channel length to determine local values of Knudsen number, Mach number and friction factor. All measurements were made in the laminar flow regime with Reynolds numbers ranging from 0.1 to 1000
115 citations
TL;DR: In this article, two channel spacings for a single corrugation angle of 20° were examined for convective heat transfer in the entrance region of corrugated channels with water as the working fluid.
Abstract: Experiments have been performed to study convective heat transfer in the entrance region of corrugated channels. With water as the working fluid, two channel spacings were examined for a single corrugation angle of 20°. The flow rate was varied over the range I50 ≤ Re ≤ 4000. Flow visualization under low-Reynolds-number flow conditions suggested the presence of longitudinal vortices, while at somewhat higher Reynolds numbers, the existence of spanwise vortices was clearly revealed. For Re > 1500, Nusselt numbers in the corrugated channels exceeded those in the parallel-plate channel by approximately 140% and 240% for the two channel spacings, the corresponding increases in friction factor being 130% and 280%. Performance evaluations under the criteria of equal mass flow rate, equal pumping power, and equal pressure drop per unit length established both the corrugated channels as superior to the parallel-plate channel in intensifying heat transfer.
114 citations
TL;DR: In this article, the quantitative characteristics of vortex structures and turbulent events in turbulent channel flows with and without drag reduction were investigated experimentally, and it was shown that the drag-reducing CTAC additive reduced both the strength and frequency of turbulent bursts near the wall, and the characteristics were not only dependent on drag reduction level but also on concentration of additive.
114 citations