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Amoranto Trisnobudi - One of the best experts on this subject based on the ideXlab platform.

  • a multi path ultrasonic transit time flow meter using a tomography method for gas flow Velocity Profile measurement
    Particle & Particle Systems Characterization, 2006
    Co-Authors: Deddy Kurniadi, Amoranto Trisnobudi
    Abstract:

    A Velocity Profile is the distribution of velocities in the axial direction over a cross-section of circular pipe. In this study, a new ultrasonic flow meter with a modified multi-path configuration, namely, a tomographic ultrasonic flow meter is proposed for the measurement of the flow Velocity Profile. The flow meter consists of a set of transmitting transducers and a set of receiving transducers placed at different positions on the pipe surroundings. This configuration produces an ultrasonic path in various directions and positions for the flow detection. Transmitting transducers, in sequence, propagate the ultrasound wave to all receiving transducers, and the axial Velocity in each ultrasonic path is measured. The average Velocity is calculated by using the weighting method. Using the theoretical flow Profiles, the tomographic ultrasonic flow meter is simulated in asymmetric flow and compared to both the diametrical and quadrature configurations. The filtered back projection method is employed to reconstruct a flow Velocity Profile. In the reconstruction process, the flow Velocity obtained in each ultrasonic path is used as the projection data. An experiment is also performed in a circular pipe for measuring the air flow Velocity Profile, in order to validate the proposed flow meter.

Jiao Zhang - One of the best experts on this subject based on the ideXlab platform.

  • analytical solutions of Velocity Profile in flow through submerged vegetation with variable frontal width
    Journal of Hydrology, 2019
    Co-Authors: Weijie Wang, Wenxin Huai, Yufei Wang, Ping Wang, Jiao Zhang
    Abstract:

    Abstract Flow within vegetation is one of the main driving forces for material exchange and energy transfer in wetland systems. Impacted by vegetation, the flow Velocity Profile illustrates distortions to the classic logarithmic Velocity Profile and has attracted much attention among researchers. Different from analytical models of Velocity distribution in literature, which is mainly suitable for vegetation with uniform frontal width, this paper establishes new analytical solutions of the Velocity Profile for vegetation such as shrub and sedge that have a variable frontal width in the vertical direction. A new shape function is proposed under these conditions in which the frontal width exhibits a gradual increase in the vertical direction from bottom up in the vegetation. Along with different closure models for eddy viscosity in the vegetation layer and surface layer, analytical solutions of the Velocity Profile are derived from the momentum equations. Good agreement between calculated and measured data shows our analytical model is effective in predicting Velocity Profiles.

Sang Joon Lee - One of the best experts on this subject based on the ideXlab platform.

  • Changes in Velocity Profile according to blood viscosity in a microchannel
    Biomicrofluidics, 2014
    Co-Authors: Eunseop Yeom, Yang Jun Kang, Sang Joon Lee
    Abstract:

    Red blood cells (RBCs) are important to dictate hemorheological properties of blood. The shear-thinning effect of blood is mainly attributed to the characteristics of the RBCs. Variations in hemorheological properties alter flow resistance and wall shear stress in blood vessels. Therefore, detailed understanding of the relationship between the hemorheological and hemodynamic properties is of great importance. In this study, blood viscosity and blood flow were simultaneously measured in the same microfluidic device by monitoring the flow-switching phenomenon. To investigate blood flows according to hemorheological variations, the flow rate of blood samples (RBCs suspended in autologous plasma, dextran- treated plasma, and in phosphate buffered saline solution) was precisely controlled with a syringe pump. Velocity Profiles of blood flows were measured by using a micro-particle image velocimetry technique. The shape of Velocity Profiles was quantified by using a curve-fitting equation. It is found that the shape of the Velocity Profiles is highly correlated with blood viscosity. To demonstrate the relationship under ex vivo conditions, biophysical properties and Velocity Profiles were measured in an extracorporeal rat bypass loop. Experimental results show that increased blood viscosity seems to induce blunt Velocity Profile with high Velocity component at the wall of the microchannel. Simultaneous measurement of blood viscosity and Velocity Profile would be useful for understanding the effects of hemorheological features on the hemodynamic characteristics in capillary blood vessels.

Omer Savas - One of the best experts on this subject based on the ideXlab platform.

Deddy Kurniadi - One of the best experts on this subject based on the ideXlab platform.

  • a multi path ultrasonic transit time flow meter using a tomography method for gas flow Velocity Profile measurement
    Particle & Particle Systems Characterization, 2006
    Co-Authors: Deddy Kurniadi, Amoranto Trisnobudi
    Abstract:

    A Velocity Profile is the distribution of velocities in the axial direction over a cross-section of circular pipe. In this study, a new ultrasonic flow meter with a modified multi-path configuration, namely, a tomographic ultrasonic flow meter is proposed for the measurement of the flow Velocity Profile. The flow meter consists of a set of transmitting transducers and a set of receiving transducers placed at different positions on the pipe surroundings. This configuration produces an ultrasonic path in various directions and positions for the flow detection. Transmitting transducers, in sequence, propagate the ultrasound wave to all receiving transducers, and the axial Velocity in each ultrasonic path is measured. The average Velocity is calculated by using the weighting method. Using the theoretical flow Profiles, the tomographic ultrasonic flow meter is simulated in asymmetric flow and compared to both the diametrical and quadrature configurations. The filtered back projection method is employed to reconstruct a flow Velocity Profile. In the reconstruction process, the flow Velocity obtained in each ultrasonic path is used as the projection data. An experiment is also performed in a circular pipe for measuring the air flow Velocity Profile, in order to validate the proposed flow meter.