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Discharge
Published in Jochen Aberle, Colin D. Rennie, David M. Admiraal, Marian Muste, Experimental Hydraulics: Methods, Instrumentation, Data Processing and Management, 2017
Jochen Aberle, Colin D. Rennie, David M. Admiraal, Marian Muste
The instruments described in this section estimate discharge non-intrusively (Table 7.1.1). They were originally designed for laboratory measurements. Subsequently, the instruments have been applied to field conditions. These instruments indirectly measure flow velocity over the flow cross section (bulk flow velocity), include measurement of the flow cross-section area, and involve the flow-continuity principle to estimate discharges. Given that the inferred flow velocity is only sampled from a portion of the cross section, they need some form of velocity indexing to estimate section-averaged velocity from the measured velocity (Section 7.6). Manufacturers typically calibrate instruments for laboratory use, and users may have to additionally calibrate instruments when using them at field sites.
Molecular Communication
Published in Indrakshi Dey, Propagation Modeling for Wireless Communications, 2022
If the movement of the particles is induced by the movement of the medium (liquid or gas) itself, the transport of molecules via advection is referred to as bulk flow. Bulk flow can be turbulent or laminar. If rough surfaces and high flow velocities contributed to the stochastic variations in the bulk flow velocity over space and time, the flow is referred to as turbulent. If the flow is not turbulent, the flow is referred to as laminar.
Effect of distance between impeller blade tip and surface on mass transfer to a local electrode in a stirred vessel in a wide range of Sc number
Published in Indian Chemical Engineer, 2022
While the diffusion coefficient DAB is a transport property of the fluid, the convective mass/heat transfer coefficient is not a property of the fluid. It’s a complicated function of some parameters. Therefore, its value is determined experimentally and depends on all the factors affecting convection. These factors are the geometry of flow system, the transport properties of fluid, the type of flow, the velocity of bulk flow and the structure of the surface to which transfer occurs. Naturally, there are a huge number of convective heat and mass transfer correlations in the literature depending upon the above-mentioned factors of the experimental system. Therefore, the powers of Re and Sc numbers in these equations are not a constant value and vary depending on the factors affecting the convective transfer. If an example is given, in the heat transfer to a circular cylinder, the power of Re number in the heat transfer correlation in the form of Nu = aRemPrn (which is the analogue form of mass transfer equation in the form of Sh = aRemScn) changes between 0.330 and 0.805 depending upon the bulk velocity range [20, p. 443].