ABOUT SELECTING THE VORTEX FLOWMETER OPTIMAL BLUFF BODY SHAPE

Vortex flow meters are becoming more widespread in many industries. This is due to the simplicity and reliability of the flow transducer, the scale linearity, the frequency measuring signal presence, low requirements for alignment and ensuring the straight sections length at the installation site, etc. Among the vortex measuring instruments, the most common are instruments with a bluff body. Such flow meters operation principle is based on measuring the vortex stripping frequency behind a streamlined body installed in the flow. In this case, the metrological characteristics are determined by the bluff body shape. Therefore, the search for the optimal sensing element shape and the hydraulic channel configuration of the flow meter as a whole remains an actual issue. The paper proposes an algorithm for solving this issue according to the criteria of the measured flow rates maximum range and the interaction efficiency of the bluff body with the measured medium flow. The first criterion value is determined from the condition that the Strouhal’s number remains unchanged; the second criterion is based on the estimation of the measured medium pressure drop and the measurement error. To realize the algorithm, simulation modeling is used in the Ansys Fluent fluid simulation software, which uses computational fluid dynamics methods. Modeling carried out for three shapes of the bluff body: a cylinder, a prism with a triangular section, a prism with a trapezoidal section, which made it possible to choose a sensitive element for further solving the multi-parameter optimization problem. Geometric features of the selected sensitive element shape, the limits of their change and boundary values are grounded. The simulation made it possible to estimate the measured flow rates range and pressure losses, as well as to determine the vortex stripping frequency, measurement error and efficiency factor for the investigated geometric model. To further improve the instrument metrological parameters, the authors proposed to supplement the primary transducer geometric model with gradual contraction and diffuser sections. These sections parameters are selected from the conditions of a continuous flow and the maximum measured flow rates range with a minimum pressure loss. The obtained results confirmed the strategy proposed by the authors. The further research prospect is to carry out simulation studies of the flow meter hydraulic channel proposed configuration for different measured media.

Brassica juncea polysaccharides induce apoptosis of colorectal cancer cells via mitochondrial- and caspasedependent apoptosis pathways

Purpose: To determine the effect of polysaccharides from Gleditsia on apoptosis of colorectal cancer cells, and the mechanism involved.Methods: Polysaccharides were extracted from Lycium barbarum, and their concentration was more than 85 %. Then, DLD-1 cells were cultured in medium with the polysaccharides at concentrations of 75 and 150 μg/mL. Cell proliferation was determined with MTT (3-(4,5)-dimethylthiahiazo (-z-y1)-3,5- diphenytetrazoliumromide) assay and colony formation assay, while apoptosis was determined with flow cytometry. Changes in MMP were measured flow cytometrically. The protein levels of PARP, Bcl-2, Bax, and caspases 3 and 9 were determined with Western blot assay.Results: Cell viability decreased time-dependently. Compared with control without polysaccharide exposure, cell viability, colony forming cells, % apoptosis, red: green fluorescence ratio, and bcl-2 expression were significantly and concentration-dependently decreased, while the expression levels of PARP, Bax, caspase-3 and caspase-8 were significantly increased (p < 0.05).Conclusion: These results indicate that the polysaccharides suppressed apoptosis of colorectal cancer cells by inhibiting the mitochondrial and caspase-dependent apoptosis pathways. Gleditsia polysaccharide may be used as an adjuvant therapy for colorectal cancer.

Beyond Janus Geometry: Characterization of Flow Fields Around Nonspherical Photocatalytic Microswimmers

Catalytic microswimmers that move by a phoretic mechanism in response to a self-induced chemical gradient are often obtained by the design of spherical janus microparticles, which suffer from multi-step fabrication and low yields. Approaches such as irregular particle shapes, local excitation or intrinsic asymmetry are on the rise to facilitate manufacturing, but the effects on the generation of motion remain poorly understood. In this work, single crystalline BiVO4 microswimmers are presented that rely on a strict inherent asymmetry of charge-carrier distribution under illumination. The origin of the asymmetrical flow pattern is elucidated becauseof the high spatial resolution of measured flow fields around pinned BiVO4 colloids. As a result the flow from oxidative to reductive particle sides was confirmed. Distribution of oxidation and reduction reactions suggests a dominant self-electrophoretic motion mechanism with a source quadrupole as the origin of the induced flows. It is shown that the symmetry of the flow fields is broken by self-shadowing of the particles and synthetic surface defects that impact the photocatalytic activity of the microswimmers. The results demonstrate the complexity of symmetry breaking in nonspherical microswimmers and are leading the way towards understanding ofpropulsion mechanisms of phoretic colloids of various shapes.

Evaluation of hydrological modeling using climatic station and gridded precipitation dataset

The conventional rainfall data estimates are relatively accurate at some points of the region. The interpolation of such type of data approximates the actual rainfield however in data scarce regions; the resulted rainfield is the rough estimate of the actual rainfall events. In data scarce regions like Indus basin Pakistan, the data obtained through remote sensing can be very useful. This research evaluates two types of gridded data i.e., European Reanalysis (ERA) interim and Japanese Reanalysis 55 years (JRA-55) along with the climatic station data for three small dams in Pakistan. Since no measured flow data is available at these dams, the nearest possible catchments where flow data is available are calibrated and the calibrated parameters of these catchments are then used in actual dams for simulating the flow from all the three types of data using Soil and Water Assessment Tool (SWAT). The results of the comparison of gridded and rainguage precipitation shows that gridded data highly overestimates the climatic station data. Similar results were observed in the comparison of flow simulated by SWAT model. The Peak flood calculated from JRA-55 overestimates while the Era-Interim peak floods are comparable to that of climatic stations in two of the three catchments.

Supplemental data table for "Stage-discharge Relationships of Drawdown Plates for Denitrifying Woodchip Bioreactors"

Table with height of water in the control structure upstream and downstream of the drawdown plate, head difference across the plate, and measured flow rate.

Supplemental data table for "Stage-discharge Relationships of Drawdown Plates for Denitrifying Woodchip Bioreactors"

Table with height of water in the control structure upstream and downstream of the drawdown plate, head difference across the plate, and measured flow rate.

Experimental investigation of shock–shock interactions with variable inflow Mach number

Experiments on shock–shock interactions were conducted in a transonic–supersonic wind tunnel with variable free-stream Mach number functionality. Transition between the regular interaction (RI) and the Mach interaction (MI) was induced by variation of the free-steam Mach number for a fixed interaction geometry, as opposed to most previous studies where the shock generator angles are varied at constant Mach number. In this paper, we present a systematic flow-based post-processing methodology of schlieren data that enables an accurate tracking of the evolving shock system including the precise and reproducible detection of RI$$\rightleftarrows $$ ⇄ MI transition. In line with previous experimental studies dealing with noisy free-stream environments, transition hysteresis was not observed. However, we show that establishing accurate values of the flow deflections besides the Mach number is crucial to achieve experimental agreement with the von Neumann criterion, since measured flow deflections deviated significantly, up to $$1.2^{\circ }$$ 1 . 2 ∘ , from nominal wedge angles. We also report a study conducted with a focusing schlieren system with variable focal plane that supported the image processing by providing insights into the three-dimensional side-wall effects integrated in the schlieren images.

Experimental Study on the Influence of Bulbous Bow Form on the Velocity Field around the Bow of a Trimaran Using Towed Underwater 2D-3C SPIV

In this study, particle image velocimetry was applied to measure the flow field around the bow region of a trimaran with different appendages. The dimensionless axial velocity u/U in test planes 1 and 2 of the testing model was measured by using a towed underwater stereoscopic particle image velocimetry (SPIV) system. Based on the measured flow field data, the local sinkage values in test planes 1 and 2 of the testing model with different appendages at speeds of 1.766 and 2.943 m/s were presented. In addition, the effects of speed, bulbous bow type, T foils, and bow wave on the axial velocity u/U were studied in detail. The acquired experimental data help in understanding the distribution of the flow field around the ship bow, and the data can also act as a reference to verify computational fluid dynamics (CFD) results.

Modal Decomposition and Linear Modeling of Swirl Fluctuations in the Mixing Section of a Model Combustor Based On PIV Data

In order to determine the flame transfer function of a combustion system, different mechanisms have been identified that need to be modeled. This study focuses on the generation and propagation of one of these mechanisms, namely the swirl fluctuations downstream of a radial swirl combustor under isothermal conditions. Swirl fluctuations are generated experimentally by imposing acoustic perturbations. Time-resolved longitudinal and crosswise PIV measurements are conducted inside the mixing tube and combustion chamber to quantify the evolution of the swirl fluctuations. The measured flow response is decomposed using spectral proper orthogonal decomposition to unravel the contributions of different dynamical modes. In addition a resolvent analysis is conducted based on the linearized Navier-Stokes equations to reveal the intrinsically most amplified flow structures. Both, the data-driven and analytic approach, show that inertial waves are indeed present in the flow response and an inherent flow instability downstream of the swirler, which confirms recent theoretical works on inertial waves. However, the contribution of the identified inertial waves to the total swirl fluctuations turns out to be very small. This is suggested to be due to the very structured forcing at the swirler and the additional amplification of shear-driven modes. Overall, this work confirms the presence of inertial waves in highly turbulent swirl combustors and evaluates its relevance for industry-related configurations. It further outlines a methodology to analyze and predict their characteristics based on mean fields only, which is applicable for complex geometries of industrial relevance.

Novel Experimental Method to Determine the Performance of Vacuum Insulated Tubing VIT for Deepwater Applications

Vacuum insulated tubing (VIT) is a specialized tubular designed to minimize heat loss from production or injection fluids to the environment in oil, gas and geothermal wells. VIT strings are used in deepwater wells for flow assurance or to mitigate annular pressure buildup. VIT use requires accurate knowledge of its insulating performance. Although VIT performance can be estimated from analytical tools, such as finite element analysis (FEA), an experimental approach provides a more direct measurement and can be used to validate analytical tools. We have developed a new experimental method to address this need. In this method, one or two VIT joints are placed in an ice-water bath. A precisely measured flow of heated air flows inside the VIT. The temperature change of the flowing air is measured between the inlet and outlet of the VIT test specimen. The insulating performance of the VIT is then calculated from this temperature difference using heat exchanger theory with effectiveness-number of transfer units (&#ξ03B5;-NTU) approach. A proportional-integral-derivative (PID) controller is used to control the air temperature at the VIT inlet by regulating power to the heater. This paper illustrates the data reduction method and uncertainty analysis using sample test data. The method allows for rapid measurement of VIT performance at many different temperatures, with the air flow rate being used to optimize the test sensitivity and to reduce experimental uncertainty. As currently designed, the apparatus is able to test single- and double-joint VITs with effective body conductivities between 0.002-0.1 W/m/°C (0.001-0.06 Btu/hr/ft/°F) and temperatures up to 400°C (750°F); however, the design allows the apparatus to be modified easily for higher or lower conductivities. Although designed for VIT, this method may be applied to other types of tubulars. Currently, there is no widely accepted standard method for experimental testing of VIT performance, and it is hoped that this new method may evolve to an industry standard.