Values Of Velocity Profiles Research Articles

Numerical analysis of thermal characteristics for micropolar fluid flux close to an isothermal vertical plate inward porous region

The merit of this manuscript is to examine numerically a heated vertical plate with uniform temperature subjected to a steady, viscous, incompressible micro-polar fluid flow that is situated inside a saturated porous medium with permeability and porosity. Similarity variables have been applied to convert coupled of constrained partial differential equations that describe physical problem into coupled of constrained nonlinear ordinary differential equations, which in turn allows for the reliable numerical solution of the problems. Finite difference and shooting methods coupled with Runge-Kutta scheme have been implemented by Matlab function bvp4c to solve equations numerically. The graphical findings showed the impact of emerging dimensionless physical parameters for micro- polar liquid on non-dimensional velocity, temperature, and micro-rotation distributions. The latest findings exhibit a high degree of agreement with the findings from earlier research. Elevating parameter values drive to an increase in the velocity profile values, but a decrease in the temperature distribution values. The benchmarks parameters of this research are modified vortex viscosity and micro-inertia density. The high porosity in the range of 0.7–0.9 is considered the noteworthy limitation of the current study. Furthermore, increasing the material's physical characteristics cause the micro-rotation vorticity profile's curvature to flip.

Theoretical analysis of modified non-Newtonian micropolar nanofluid flow over vertical Riga sheet

The main purpose of this work is to study the steady incompressible second-grade micropolar fluid flow over a nonlinear vertical stretching Riga sheet. Velocity slip and zero mass flux are considered at the solid surface of Riga shape such that the friction of nanoparticle maintains itself with strong retardation. The influence of Lorentz forces produced by the Riga plate is an important aspect of the study. The influences of thermophoresis and Brownian motion under the heat generation and e bouncy forces are studied on the nonlinear vertical Riga sheet. The mathematical model is developed under the flow assumptions. The mathematical model in terms of partial differential equations is formed by implementing the boundary layer approximations. The partial differential equations are further reduced to ordinary differential equations by means of suitable transformations. The ordinary differential equations are solved through the numerical procedure. The variations in the horizontal movement of nanofluid, thermal distribution and concentration distribution of the nanoparticle have been noted for different fluid parameters. The values of velocity profile and temperature profile are larger in the case of injection ([Formula: see text] as compared to suction ([Formula: see text]). The values of concentration distribution are smaller in the case of injection ([Formula: see text] as compared to suction ([Formula: see text]. The validation of this analysis with decay literature is provided in the form of tables.

Noise Limitations on the Recovery of Average Values of Velocity Profiles in Pipelines by Simple Imaging Systems

This letter deals with a recently proposed two-step algorithm for the reconstruction of dielectric and velocity profiles of axially moving cylinders. In particular, the aim of the present work is to investigate the limitations and capabilities in reconstructing the velocity profile. By considering a best-case scenario, it is shown that, although the algorithm should be able to work even in the presence of flows with very small axial velocity values, reliable results can only be obtained when the axial speed is larger than a lower bound. This bound is shown to be an intrinsic limitation of the algorithm which is only related to the cross-polarization isolation of the measurement system. Other simulations, based on worst-case scenarios, confirm that such a bound is independent of the type of flow considered, of the configuration of the measurement system, and of the errors coming from the step devoted to the reconstruction of the dielectric profile. Finally, the same simulations show that the algorithm is reliable in a wide range of speed values, provided sensors with large cross-polarization isolations are exploited.

Characterization of particle deposition in a lung model using an individual path

Suspended particles can cause a wide range of chronic respiratory illnesses such as asthma and chronic obstructive pulmonary diseases, as well as worsening heart conditions and other conditions. To know the particle depositions in realistic models of the human respiratory system is fundamental to prevent these diseases. The main objective of this work is to study the lung deposition of inhaled particles through a numerical model using UDF (User Defined Function) to impose the boundary conditions in the truncated airways. For each generation, this UDF puts the values of velocity profile of the flow path to symmetrical truncated outlet. The flow rates tested were 10, 30 and 60 l/min , with a range of particles between 0.1 µm and 20 µm .

OC91: Multigate spectral Doppler analysis (MSDA) to study hemodynamic parameters during IVF treatment for egg donation cycles

Objectives: In this study multigate spectral Doppler analysis, a novel ultrasound technology that overcomes the limitations related to the use of a single sample volume, has been applied to the evaluation of hypogastric (Ha) and uterine (Ut) artery flow during IVF treatment, specifically egg donor and recipient cycles. Methods: MSDA using MyLab (Esaote, Florence) was carried out at baseline, during ovulation induction and at egg retrieval in the egg donors, and at baseline and embryo transfer time in the recipients. The analysis in real time included velocity profile (VP), relative wall distension rate (rWDR) and wall shear rate (WSR) of Ha and Ut in the donors and only in Ut for the recipients. Results: A total of 10 egg donors (mean age 24.3 ± 1.8 years) and six recipients (mean age 42.6 ± 3.4 years) were found eligible for the study and successfully evaluated. Compared to conventional spectral Doppler, MSDA revealed different shapes of velocity profiles. There were no significant differences in VP, rWDR and WSR between egg donors at the time of egg retrieval and recipients at the time of embryo transfer in Ut. The rWDR was inversely related to gravity, parity and hematocrit (Hct) (P < 0.05). The WSR of both Ha and Ut were correlated with Hct and the FSH at day 3 (rs = 0.9, P < 0.05). Recipients who conceived had a lower mean WSR (R = 338.3, L = 326.6) than those who did not (R = 512.9, L = 766.3; P < 0.05). WSR of recipients was inversely correlated with positive pregnancy test (rs = −0.878, P < 0.05) bilaterally, while WSR of egg donors was not. Conclusions: This is the first study to provide basic physiological values of VP, rWDR and WSR in patients undergoing ovulation induction for IVF. The measurements in egg donors are to be considered as reference values for patients undergoing IVF since they are young and their ovarian response optimal. Likewise, given the high pregnancy rate in the recipients, the results should be considered promising but not definitive.