Ultrasound Doppler velocimetry

J. Bouillard, B. Alban, P. Jacques, C. Xuereb 2001, (Liquid flow velocity measurements in stirred tanks by ultrasound doppler velocimetry), Chem. Eng. Sci. 56, 747. 

Ultrasound Doppler velocimetry (UDV) has also been used to measure bubble velocity by measuring the frequency shift between the emitted ultrasound beam and the echo reflected from the gas-liquid interface (Vial et al., 2003). 

The method of ultrasound Doppler velocimetry (UDV) [9] was proposed to measure the viscosity of non-Newtonian fluids over a wide range of shear rates and in a short period of time. This is a noninvasive, nondisturbing, quick, and accurate procedure. The distribution of shear-stress can be found by pressure drop. At a radial position, the ratio of shear-stress to shear rate, by definition, yields the viscosity at that point. Thus, for the shear rate range in the flow, viscosity values can be obtained by means of only one online experiment. This is a method known in the literature as pointwise rheological measurement [10,11]. 

Koseli V, Zeybek S, Uludag Y. Online viscosity measurement of complex solutions using ultrasound doppler velocimetry. Turk J Chem 2006 30 297-305. 

Ultrasonic Doppler velocimetry, 3 Ultrasonic velocity profiler (UVP) measurements, 1, 2, 4. See also Gas-liquid interface Ultrasound echo intensity, 10-11, 13-15, 20... 

Real-time wall shear stress is difficult to monitor precisely because it varies in space and time. MEMS sensors provide high spatial resolution to resolve variations in shear stress in a 3D bifurcation model for small-scale hemodynamics. The application of MEMS sensors with backside wire bonding G ig. fib) captured the spatial variations in shear stress in a 3D bifurcation model (Fig. 8). The measured skin friction coefficients at various positions correlated well with values derived from the exact Navier-Stokes solution of the flow within the bifurcation [13]. Therefore, the development of MEMS sensors has enabled the precise measurements of spatial variations in shear stress for small-scale hemodynamics otherwise difficult with conventional technologies such as computed tomography (CT scan), magnetic resonance imaging (MRI), ultrasound, and laser Doppler velocimetry. 

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