Modelling and simulation of fluid flow through a circular cylinder with high reynolds number: a COMSOL multiphysics study

In this study, we intend to investigate the steady-state and laminar �ow of a viscous �uid through a circular cylinder �xed between two parallel plates keeping the aspect ratio of 1 : 5 from cylinder radius to height of the channel. �e two-dimensional, in�compressible �uid �ow problem has been simulated using COMSOL Multiphysics 5.4 which implements �nite element’s procedure. �e �ow pattern will be investigated by using the Reynolds number from 100 to 1000. �e reattachment length formed at the back of the cylinder and drag force when the �uid comes to strike with the front surface of the cylinder is expressed in terms of Reynolds numbers. We propose to calculate the velocity and the pressure before and after the cylinder. For this purpose, two�line graphs before and after the cylinder will be drawn to check the impact of cylinder on both velocity and pressure. It was found that the percentage change in the velocity as well as pressure before to after the cylinder is changing their behaviours at Re � 700. �e study is important because the empirical equations between the vortex’s lengths formed along the cylinder using the linear regression process obtained in this study may be used for future implementatio

Finite Element Analysis of Fluid Flow through the Screen Embedded between Parallel Plates with High Reynolds Numbers

This paper provides numerical estimation of Newtonian fluid flow past through rectangular channel fixed with screen movable from 10° to 45° by increasing the Reynolds number from 1000 to 10,000. The two-dimensional incompressible Navier Stokes equations are worked out making use of the popular software COMSOL MultiPhysics version 5.4 which implements the Galerkin’s least square scheme to discretize the governing set of equations into algebraic form. In addition, the screen boundary condition with resistance coefficient (2.2) along with resistance coefficient 0.78 is implemented along with slip boundary conditions applied on the wall. We engaged to find and observe the relationship between the optimum velocity, drag force applied by the screen, and pressure occurred in the channel with increasing Reynolds number. Because of the linear relationship between the optimum velocities and the Reynolds number, applying the linear regression method, we will estimate the linear equation so that future prediction and judgment can be done. The validity of results is doing with the asymptomatic solution for stream-wise velocity at the outlet of the channel with screens available in the literature. A nondimensional quantity, i.e., ratio from local to global Reynolds number Rex/Re, is introduced which found stable and varies from -0.5 to 0.5 for the whole problem. Thus, we are in the position to express the general pattern of the velocity of the particles as well as the pressure on the line passing through the middle of the channel and depart some final conclusion at the end

Analysis of Power Law Fluids and the Heat Distribution on a Facing Surface of a Circular Cylinder Embedded in Rectangular Channel Fixed With Screen: A Finite Element’s Analysis

The current article is an understanding of heat transfer and non-Newtonian fluid flow with implications of the power-law fluid on a facing surface of the circular cylinder embedded at the end of the channel containing the screen. The cylinder is fixed with an aspect ratio of 4:1 from height to the radius of the cylinder. The simulation for the fluid flow and heat transfer was obtained with variation of the angle of screen $\frac {\pi }{6}\le \theta \le \frac {\pi }{3}$ , Reynolds number 1000 ≤ Re ≤ 10, 000 and the power-law index $0.7\le n\le 1.3$ by solving two-dimensional incompressible Navier-Stokes equations and the energy equation with screen boundary condition and slip walls. The results will be in a good match with asymptotic solution given in the literature. The results are presented through graph plots for non-dimensional velocity, temperature, mean effective thermal conductivity, heat transfer coefficient, and the local Nusselt number on the front surface of the circular cylinder. It was found that the ratio between the input velocity to the present velocity on the surface of the circular cylinder remains consistent and reaches up to a maximum of 2.2% and the process of heat transfer does not affect by the moving of the screen and clearly with the raise of power-law indexes the distribution of the heat transfer upsurges. On validation with two experimentally derived correlations, it was also found that the results obtained for the shear-thinning fluid are more precise than the numerically calculated results for Newtonian as well as shear-thickening cases. Finally, we suggest necessary measures to enrich the development of convection when observing with strong effects influenced by the screens or screen boundary conditions

Finite Element Least Square Technique for Newtonian Fluid Flow through a Semicircular Cylinder of Recirculating Region via COMSOL Multiphysics

This article aims to study Newtonian fluid flow modeling and simulation through a rectangular channel embedded in a semicircular cylinder with the range of Reynolds number from 100 to 1500. The fluid is considered as laminar and Newtonian, and the problem is time independent. A numerical procedure of finite element’s least Square technique is implemented through COMSOL multiphysics 5.4. The problem is validated through asymptotic solution governed through the screen boundary condition. The vortex length of the recirculating region formed at the back of the cylinder and orientation of velocity field and pressure will be discussed by three horizontal and four vertical lines along the recirculating region in terms of Reynolds number. It was found that the two vortices of unequal size have appeared and the lengths of these vortices are increased with the increase Reynolds number. Also, the empirical equations through the linear regression procedure were determined for those vortices. The orientation of the velocity magnitude as well as pressure along the lines passing through the center of upper and lower vortices are the same

Finite Element Analysis of Air Flow and Temperature Distribution on Surface of a Circular Obstacle with Resistance and Orientation of Screen

Nonisothermal flow through the rectangular channel on a circular surface under the influence of a screen embedded at the middle of a channel at angles θ is considered. Simulations are carried out via COMSOL Multiphysics 5.4 which implements the finite element method with an emerging technique of the least square procedure of Galerkin’s method. Air as working fluid depends upon the Reynolds number with initial temperature allowed to enter from the inlet of the channel. The nonisothermal flow has been checked with the help of parameters such as Reynolds number, angle of the screen, and variations in resistance coefficient. The consequence and the pattern of the velocity field, pressure, temperature, heat transfer coefficient, and local Nusselt number are described on the front surface of the circular obstacle. The rise in the temperature and the flow rate on the surface of the obstacle has been determined against increasing Reynolds number. Results show that the velocity magnitudes are decreasing down the surface and the pressure is increasing down the surface of the obstacle. The pressure on the surface of the circular obstacle was found to be the function of the y-axis and does not show any impact due to the change of the resistance coefficient. Also, it was indicated that the temperature on the front circular surface does not depend upon the orientation of the screen and resistance factor. The heat transfer coefficient is decreasing which indicates that the conduction process is dominating over the convection process

Effectiveness of Pre-Trained CNN Networks for Detecting Abnormal Activities in Online Exams

Online exams are growing increasingly popular in organizations and educational institutes because they are more flexible and cost-effective than conventional paper-based exams. When face-to-face exams are not possible, such as during floods, unexpected situations, or pandemics like COVID-19, this exam mod has become even more popular and important. However, online exams may have difficulties, such as the need for a reliable internet connection and the possibility of cheating. Because there is no human supervisor present to monitor the exam, so cheating is a major concern. The environment employed for the online exams ensures that every student finalizes the evaluation process without using any type of cheating. This study investigates the detection and recognition of unusual behavior in an academic setting, such as online exams, to prevent students from cheating or engaging in unethical behavior. After consulting with experts and reviewing the online exam held in Covid-19 and other online exams, selected the four most common cheating activities found in the online exam. The study extracts key frames using motion-based frame extraction techniques before employing advanced deep learning techniques with various convolutional neural network configurations. This study presents several deep learning-based models that analyze the video exam to classify four categories of cheating. This method extracts key frames from a video sequence/stream based on human motion. This research developed a real dataset of cheating behaviours and conducted comprehensive experiments with pre-trained and suggested deep-learning models. When evaluated using standard performance criteria, the YOLOv5 model outperforms other pre-trained and fine-tuned approaches for detecting unusual activity

Prevalence of Glomerular Diseases: King Khalid University Hospital, Saudi Arabia

To obtain a more recent and comprehensive insight into the prevalence of glomerular diseases in our patient population, medical records of 200 patients with biopsy proven glomerulonephritis (GN), between January 1994 and June 1999, at the King Khalid University Hospital, Riyadh, Saudi Arabia were analyzed. Primary glomerular disease was found to be the most prevalent, accounting for 63.5% of all glomerular diseases. Among primary glomerular diseases, focal and segmental glomerulosclerosis (FSGS) was the most common histological lesion (34.6%) and was associated with a high prevalence of hypertension (86.4%), nephrotic syndrome (68.18%), hematuria (63.6%) and renal functional impairment (27.3%). Mesangioproliferative GN was the second most common lesion (25.1%) followed by mesangiocapillary GN (15.7%), IgA nephropathy (10.2%), and minimal change disease (8.5%). Amongst secondary glomerular diseases, lupus nephritis was the most prevalent (24.5%). In conclusion, primary glomerular diseases constituted the commonest group encountered and the prevalence of FSGS was quite high with male sex and young adults predominating. FSGS was also associated with a high prevalence of end-stage renal disease. Further collaborative studies are necessary to explore the predisposing factors and associations of glomerular disease, especially FSGS