Dispersion of a solute in a Herschel–Bulkley fluid flowing in a conduit

The dispersion of a solute in a Herschel-Bulkley fluid is studied by using the generalized dispersion model in both pipe and channel. With this method the entire dispersion process is described as a simple diffusion process with the effective diffusion coefficient as a function of time. The results for Newtonian fluid, power law fluid and Bingham fluid are obtained as special cases by giving appropriate values to the power law index and yield stress. The effects of power law index, yield stress on the dispersion coefficient and mean concentration have been discussed computationally and graphically. The effect of power law index and yield stress is found to reduce the dispersion coefficient. It is observed that the critical time for dispersion coefficient to reach the steady state is varying with the yield stress and power law index. It is noticed that time to assume the critical value in Newtonian case is 0.5 and in the channel case the corresponding value of time is 0.55 which are in agreement with the existed results. It is also observed that in the non- Newtonian fluids this time is less than that of Newtonian fluid case and in Bingham fluid the critical value of time in pipe flow analysis (channel flow analysis) is attained at 0.45 (0.52) while in power law fluid it is at 0.43(0.48) and in the case of Herschel-Bulkley fluid it is 0.41 (0.45)

Heat transfer analysis in the non-orthogonal flow of a non-Newtonian nanofluid with non-linear thermal radiation

This analysis pertains to the non-Newtonian nanofluid impinging the surface of stretching obliquely. The base fluid under discussion obeys the constitutive equation of a UCM fluid. Use of similarity variables and RKF 45 numerical method along with shooting technique enabled us to obtain the solution of the problem. The effects of physical parameters associated with nanofluids on the flow variables are discussed in detail through graphs. The streamlines are skewed towards right of the stagnation point when the stagnation flow parameter is negative and towards left for positive values. Due to Brownian motion, thermophoresis and nonlinear thermal radiation temperature is enhanced. Brownian motion and chemical reaction have an increasing influence on Sherwood number while a reversal effect is noticed with thermophoresis. The results of this study are compared with those available in the existing literature and are found to be in good agreement. Keywords: Maxwell fluid, Nanofluid, Non-orthogonal flow, Non-linear thermal radiation, Streamline

Dual Solutions Of An Unsteady Flow, Heat And Mass Transfer Of An Electrically Conducting Fluid Over A Shrinking Sheet In The Presence Of Radiation And Viscous Dissipation

In this study we analyze the effects of thermal radiation and surface mass transfer on the flow generated by a shrinking sheet. Homotopy analysis method (HAM) is employed to obtain analytical solutions for the flow, temperature and mass concentration fields. The plots for the velocity, temperature and concentration fields are presented and their behavior is discussed for several sets of values of the governing parameters. Dual solutions are observed to exist for the shrinking sheet problem. Surface drag coefficient of the stable solution is enhanced for increasing values of the magnetic parameter and suction parameter. Also, thermal radiation parameter and Eckert number increase the rate of heat transfer in the case of stable solution. However, mass transfer rate of the stable solution is noticed to be a decreasing function of Schmidt number and chemical reaction parameter. We expect that the results obtained will not only provide useful information for industrial applications but also complement the existing literature

Magnetic Field Effect on Poiseuille Flow and Heat Transfer of Carbon Nanotubes along a Vertical Channel Filled with Casson Fluid

Applications of carbon nanotubes, single walls carbon nanotubes (SWCNTs) and multiple walls carbon nanotubes (MWCNTs) in thermal engineering have recently attracted significant attention. However, most of the studies on CNTs are either experimental or numerical and the lack of analytical studies limits further developments in CNTs research particularly in channel flows. In this work, an analytical investigation is performed on heat transfer analysis of SWCNTs and MWCNTs for mixed convection Poiseuille flow of a Casson fluid along a vertical channel. These CNTs are suspended in three different types of base fluids (Water, Kerosene and engine Oil). Xue [Phys. B Condens. Matter 368, 302–307 (2005)] model has been used for effective thermal conductivity of CNTs. A uniform magnetic field is applied in a transverse direction to the flow as magnetic field induces enhancement in the thermal conductivity of nanofluid. The problem is modelled by using the constitutive equations of Casson fluid in order to characterize the non-Newtonian fluid behavior. Using appropriate non-dimensional variables, the governing equations are transformed into the non-dimensional form, and the perturbation method is utilized to solve the governing equations with some physical conditions. Velocity and temperature solutions are obtained and discussed graphically. Expressions for skin friction and Nusselt number are also evaluated in tabular form. Effects of different parameters such as Casson parameter, radiation parameter and volume fraction are observed on the velocity and temperature profiles. It is found that velocity is reduced under influence of the exterior magnetic field. The temperature of single wall CNTs is found greater than MWCNTs for all the three base fluids. Increase in volume fraction leads to a decrease in velocity of the fluid as the nanofluid become more viscous by adding CNTs

Unsteady Casson nanofluid thin film flow over a stretching sheet with viscous dissipation and chemical reaction

The current research work is devoted to study the exploration of dissipation and chemical reaction on MHD radiative Casson nanoliquid thin film flow generated due to the sheet stretching. Brownian motion, viscous dissipation, radiation and chemical reactions are considered, respectively, in energy and concentration equations. The popularly used similarity variables are utilized to remodel the nonlinear partial differential equations to a system of ordinary differential equations. The computational results are obtained for this system by adopting shooting technique. The impressions of significant flow variables on liquid stream are obtained through diagrams and tables. The outcomes of current work conclude that the thickness of thin film decreases with the rise of unsteady, magnetic and Casson parameters. Also, for higher estimates of non-Newtonian parameter a reduction in the coefficient of wall friction is noticed. The outcomes are matched with the viscous fluid flow and the results are in better agreement as a limiting case

Emerging co-infections in dengue: A study at tertiary care Govt. general hospital

Background: Infection with two agents might cause overlapping symptoms, confusing the treating physician. This study aims to determine the current coinfections rates in dengue patients in a tertiary care Govt. General Hospital, Anathapuramu. Method: From July 2021 to November 2021, an observational study was conducted at the Government Medical College & Hospital in Ananthapuramu. A total of 100 clinically suspected Dengue patients were included in this research. Blood samples from 100 patients who visited the General Medicine and Pediatrics OPD were taken and sent to the lab for the diagnosis of Dengue and other co-infections. Result: In our study, Out of 100 samples, 32 samples tested positive for Dengue by RTPCR. Out of 32 samples tested positive by RTPCR, two samples were positive for DENV-1, 26 samples were positive for DENV-2, and four samples were positive for DENV-3, according to RTPCR results. Dengue with co-infection was detected in 21 individuals, with 1 (3.125%) being MP-ICT positive, 2 (6.25%) being salmonella WIDAL positive, 1 (3.125%) being Scrub typhus IgM reactive, 4 (12.5%) being chikungunya IgM positive, 9 (28.125%) being UTI positive, and 4 (12.5%) having Blood Stream Infections