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The aim of this comment is to point out three major errors in the paper Akolade et al. (2024). [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

The flow induced by a sphere rotating inside an incompressible, non-Newtonian, Carreau fluid has been investigated numerically. The rotating sphere is enclosed in a concentric cubic box with solid boundaries. The fluid power-law index varied between 0.2 and 2 thereby covering both shear-thinning and shear-thickening fluids, the Reynolds number varied between 0.01 and 1000 and the Carreau number varied between 1 and 1000. The torque applied on the sphere has been calculated and is presented in tables and figures. It was found that at low Reynolds numbers the torque is independent of the Reynolds number and increases with increasing the power-law index. As the Carreau number increases the torque decreases in shear-thinning fluids and increases in shear-thickening fluids. In all cases, four vortices appear at the vertical plane passing through the sphere centre. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

The flow past a sphere, rigidly held between two parallel plates (Couette flow), was studied in a non-Newtonian, power-law fluid, numerically. The three momentum equations have been solved under the following conditions: creeping flow with Re < 1; power-law index 0.2–1; distance of sphere center from the plates 1.15–10; sphere position between the plates 0.1–0.9. Diagrams have been produced for the direct calculation of the force acting on the sphere. The numerical forecast shows a significant disparity between Newtonian and non-Newtonian fluids. All in all, the wall effect in power law fluids is less extreme than in Newtonian fluids. Furthermore, in non-Newtonian fluids, the force changes linearly when the sphere approaches the upper plate. [ABSTRACT FROM AUTHOR]

The flow of a non-Newtonian, power-law fluid, directed normally to a rotating sphere is considered in the present paper. The problem is investigated by means of a three-dimensional numerical simulation with the SIMPLE algorithm. The investigation covers the power-law index from 0.2 up to 2, rotation rate from 0.1 up to 3 and Reynolds number from 0.1 up to 100. The following general rules are valid. The lift coefficient increases with increasing the rotation rate. At high Re numbers the drag coefficient increases with the power-law index. At high Re numbers the torque coefficient increases with the power-law index and with the rotation rate, whereas the torque coefficient reduces as the Reynolds number increases. In addition, there are some special cases which are analyzed in the text. [ABSTRACT FROM AUTHOR]

There is no correct form of the term HT ht in the literature. In Physics it is not allowed to add quantities with different units and the term HT ht is wrong. [Extracted from the article]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Abstract Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Abstract Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Hundreds of papers are published each year in the field of boundary layer flow. However, in many papers serious errors appear. In the present paper an attempt has been made to summarize these errors. Unlabelled Image • Error concerning truncation of profiles • Error concerning contradiction between pdf and transformed ode • Error using the local similarity method in non-similar problems • Error using dimensional parameters instead of non-dimensional parameters [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

In the above paper, there are some typographical errors and some serious errors. [ABSTRACT FROM AUTHOR]

The equations studied in the above paper are dimensionally incorrect. [ABSTRACT FROM AUTHOR]

The present comment concerns some doubtful results included in the above paper. [ABSTRACT FROM AUTHOR]

The flow induced by a sphere rotating inside a non-Newtonian, Bingham fluid has been investigated numerically. The rotating sphere is enclosed in a concentric cubic box with solid boundaries. The Bingham number varied between 0.01 and 100,000 and the Reynolds number varied between 0.01 and 10,000. The torque increases with the Bingham number and reaches an asymptotic state at large Bn. The torque is independent of the Reynolds number at high Bn. The yielded region around the sphere has been determined and an empirical equation is found for its extent. [ABSTRACT FROM AUTHOR]

The flow induced by a sphere rotating inside an incompressible, non-Newtonian, power law fluid has been investigated numerically. The rotating sphere is enclosed in a concentric cubic box with solid boundaries. The fluid power-law index varied between 0.2 and 2 thereby covering both shear-thinning and shear-thickening fluids and the Reynolds number varied between 0.01 and 10,000. Numerical predictions show significant differences between shear-thinning and shear-thickening fluids. In the first case the flow is confined near the sphere whereas in the second case the flow extends up to the box plates. In creeping flow and shear-thinning fluids the torque is independent of the Reynolds number. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some typographical and serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

A serious error exists in the above paper. [ABSTRACT FROM AUTHOR]

The correct form is 5 HT ht Graph Fourth error (serious) The equation (21) in [[1]] is as follows 6 HT ht Graph Equation (6) is a dimensionless equation presented in [[1]] after the non-dimensionalization in equation (17) in [[1]]. [Extracted from the article]

The flow around a horizontal square cylinder with uniform suction or injection at the front and rear sides is considered in the present paper. The problem is investigated numerically with a finite volume method using the SIMPLE algorithm. This flow has been investigated in the past for Reynolds numbers greater than 70. In the present work, the investigation is extended to very low Reynolds numbers (up to 0.001, Stokes flow) including eight different cases concerning suction-injection at the two sides. It is found that the drag coefficient takes negative and zero values in many cases and varies linearly at low Re numbers. In all eight cases, the vortices around the cylinder have been calculated. It is found that at low Re numbers, some vortices are symmetrical both about the horizontal and vertical cylinder axes. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

The present comment concerns some doubtful results included in the above paper. [ABSTRACT FROM AUTHOR]

Highlights • The problem concerns slip flow of carbon–water nanofluid. • Three non-dimensional parameters are wrong. • Some profiles are truncated and wrong. [ABSTRACT FROM AUTHOR]

All velocity profiles in the above paper appear to be questionable and thus may include serious numerical deviations with respect to the correct solutions. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [Display omitted] [ABSTRACT FROM AUTHOR]

In a recent paper by Makinde the effect of thermal buoyancy along a moving vertical plate with internal heat generation was considered. The plate thermal boundary condition was a convective condition with a heat transfer coefficient proportional to x-1/2. The fluid thermal expansion coefficient was proportional to x-1, and the internal heat generation was assumed to decay exponentially across the boundary layer and proportional to x-1 in order that the problem accepts a similarity solution. In the present work, the same problem without heat generation is considered, with constant heat transfer coefficient and constant thermal expansion coefficient which is more realistic and has much more practical applications. The present problem is non-similar and results are obtained with the direct numerical solution of the governing equations. The problem is governed by the Prandtl number, the non-dimensional distance along the plate and a convective Grashof number, which is introduced for the first time. It is found that the wall shear stress, the wall heat transfer, and the wall temperature all increase with increasing distance and the wall temperature tends to one. The influence of the convective Grashof number is to increase the wall shear stress and the wall heat transfer and to reduce the wall temperature. [ABSTRACT FROM AUTHOR]

The present comment concerns some doubtful mathematical calculation that produced misleading results which are presented in the above paper. [ABSTRACT FROM AUTHOR]

Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]

The two basic equations in the mentioned article are wrong. [ABSTRACT FROM AUTHOR]

The present note presents some errors in the aforementioned paper published in Mathematical Methods in the Applied Sciences. Two errors are found in the definition of the non-dimensional parameters and correct results are presented for temperature profiles included in figure 10 of the previous paper. [ABSTRACT FROM AUTHOR]

Computational fluid dynamics (CFD) methods are employed to evaluate the influence of temperature variations on the flow field in an actual sedimentation tank for potable-water treatment. A series of experimental measurements of temperature variation has been conducted in that sedimentation tank. The mixed-convection problem caused by the density variations and the horizontal stream is considered at low temperatures (0-10°C) where the variation of water density is strongly nonlinear. Three cases have been examined: (1) one in the ascending, (2) one in the descending parabolic density region, and (3) one in the linear density region. The thermophysical properties of water have been incorporated into the CFD code. All simulations have been conducted for a transient, turbulent flow field. The momentum exchange between the primary and the secondary phase (particles) is considered. The results show that in the parabolic density region, only a few particles are trapped in the bottom, whereas many of them float near the surface and escape from the tank causing a low-tank efficiency. The opposite happens in the linear-density region where the tank efficiency is much better. [ABSTRACT FROM AUTHOR]

The present note treats a special case of a previous work published in Acta Mechanica (Kumari and Nath in Acta Mech 146:139-150, 2001). Analytical and asymptotic solutions are presented not found in the previous paper. [ABSTRACT FROM AUTHOR]

Lamella gravity settlers are often used in water treatment to make sedimentation tanks more cost-effective. Effective surface area for settlement is increased by the inclined plates giving such systems a smaller footprint than the conventional tanks. In this paper a numerical model was used to simulate the dynamics and flow structure of a rectangular sedimentation tank for potable water through a multiphase approach, using computational fluid dynamic (CFD) methods. Two configurations have been examined, one with a system of inclined parallel plates (lamellar settlers) and another with a conventional design, in order to evaluate the influence of lamellar settlers in the process efficiency. Unlike most of the previous numerical investigations which studied the lamellar settlers separately, the present numerical approach studies the whole sedimentation tank with a full scale system of inclined parallel plates. The momentum exchange between the primary and the secondary phase (particles) is taken into account, using a Lagrangian method (discrete phase model) with two-way coupled calculations. Contours of stream function, velocity and concentration are presented, as well as the velocity and concentration profiles for the inclined plates. The results show that the lamellar settlers influence the flow field and increase the sedimentation efficiency by 20% in comparison with the convectional design. [ABSTRACT FROM AUTHOR]

Some errors exist in the above paper. [ABSTRACT FROM AUTHOR]

Some serious errors exist in the above paper. [ABSTRACT FROM AUTHOR]