Optimization of cylindrical wall domes via metaheuristic algorithms

Optimization is a widely used phenomenon in various problems and fields. Because time and resources are very limited in today's world, it can be said that the usage area of the optimization process will be expanded and spread in all areas of life. Although different methods are used in the realization of the optimization process, the performance of metaheuristic algorithms in solving problems has led to an increase in research on these methods. As in other fields, the application examples of these algorithms are diversifying and increasing in the field of structural engineering. In this study, the performance comparison of five different algorithms for the optimum design of an axisymmetric cylindrical wall with a dome is investigated. These algorithms are Jaya (JA), Flower pollination (FPA), teaching-learning-based optimization (TLBO) algorithms and two hybrid versions of these algorithms. ACI 318 regulation was used in reinforced concrete design with a flexibility method-based approach in the analyses. In the analyzes with five different situations of the wall height, some statistical values , and data of analysis numbers were obtained by running the algorithms a large number of times. According to the analysis results, Jaya algorithm is slightly better in terms of the speed of reaching the optimum result, but also all algorithms are quite effective and reliable in solving the problem.

Wood ants express uncertainty when engaging with magnetic cues for directional guidance

Wood ants were trained indoors to follow a route in a chosen magnetic direction from the centre of a small, circular arena to find a drop of sucrose at the edge. The arena, surrounded by a white cylindrical wall, was in the centre of a 3D coil system that generated an inclined Earth strength magnetic field in any horizontal direction. Between trials, the chosen magnetic training direction was rotated to a new orientation. Tests were given without food and with fresh or reversed paper on the floor of the arena. In a significant number of tests, ants left the centre facing the goal, or in the opposite direction, but they mostly failed to reach the goal. Tests given early in the day, before any training, show that ants remember the magnetic route direction overnight. On some training trials, the position of the sucrose was also indicated by a black stripe. Not uncommonly, ants first moved in the opposite direction to the stripe before switching to the correct direction. Travel away from the reward seems to express the ant's uncertainty about the correct path to take. Tests show that this uncertainty may stem from competing directional cues linked to the room, suggesting that ants are reluctant to rely on magnetic information alone. We conclude that ants can remember a route direction defined by an Earth-strength magnetic field and that they express any uncertainty about the correct direction by moving for a stretch in the opposite direction. In a second experiment, an upright and an inverted triangle were fixed 90° from each other to the inside of the cylinder. Sucrose was placed beneath one of the triangles, dependent on the direction of the magnetic field. Ants failed to master this task and to approach the magnetically cued triangle. Instead, they preferred to approach the upright triangle. The ants were again uncertain of the correct direction and expressed this uncertainty through paths that had segments directed towards both the inverted and the upright triangles.

The effect of dome properties on design of the axial symmetric cylindrical wall

The usage of computer software in civil engineering has expanded in last decades. Many general-purpose and special-purpose commercial programs perform a very important function, especially at the design stage. In this study, a computer program is introduced for the analysis and design of the axial symmetric cylindrical wall considering the dome effects. Analysis processes are carried out according to Flexibility theory with long wall assumption and during the reinforced concrete (RC) design of the wall, ACI 318-Building code requirements for structural concrete are considered. In numerical investigation, the effects of the dome properties (thickness and height) on the analysis and design of the wall are investigated by performing a totally 72 case analyzes. These cases include different support condition at bottom of the wall, wall heights, dome thicknesses and heights. According to analysis results, it is concluded that effects of dome thickness and heights on the wall on the wall are very limited.

The mechanism of vortex instability in electromagnetically driven flow in an annular thin layer of electrolyte

A circumferential flow of a conducting fluid in an annular channel can be created by the action of a Lorentz force arising as a result of the interaction between an applied vertical magnetic field and a radial electric current flowing through the electrolyte. Quite unexpectedly, experiments revealed that a robust vortex system appears near the outer cylindrical wall in such flows. McCloughan and Suslov (J. Fluid Mech. 887:A23, 2020) (McCS) reported comprehensive linear stability results of such a flow for variable Lorentz forcing. Here we complement that study by investigating the flow structure as a function of the channel aspect ratio. Remarkably, despite the completely different physical nature of parametric dependences, dynamic in McCS and purely geometric here, we show that in both scenarios vortices appear on a background of a steady axisymmetric flow at the boundary between two counter-rotating toroidal structures and have a similar energy distributions. The two studies demonstrate the robustness of the mechanism responsible for the vortex formation: Rayleigh's inviscid centrifugal instability aided by radial shear in the boundary layer near the outer cylindrical wall. References P. A. Davidson. An introduction to magnetohydrodynamics. Cambridge University Press, 2nd edition, 2017. doi:10.1017/CBO9780511626333. J. McCloughan and S. A. Suslov. Linear stability and saddle–node bifurcation of electromagnetically driven electrolyte flow in an annular layer. J. Fluid Mech., 887:A23.1–30, 2020. doi:10.1017/jfm.2020.29. J. Perez-Barrera, J. E. Perez-Espinoza, A. Ortiz, E. Ramos, and S. Cuevas. Instability of electrolyte flow driven by an azimuthal Lorentz force. Magnetohydrodynamics, 51(2):203–213, 2015. http://mhd.sal.lv/contents/2015/2/MG.51.2.4.R.html. S. A. Suslov, J. Perez-Barrera, and S. Cuevas. Electromagnetically driven flow of electrolyte in a thin annular layer: Axisymmetric solutions. J. Fluid Mech., 828: 573–600, 2017. doi:10.1017/jfm.2017.551.

Mathematic model for describing the stress-tension behavior of an autoclave with integrated heating element

This paper describes a mathematical model and the method for determining the thermal stress fields in a cylindrical wall element of a pressure vessel with a built-in heating element and a layer of heat insulating material. The method presented is based on the calculation of contact pressures.

Analytical study of cylindrical tanks including soil-structure interaction

An analytical study aiming the design of cylindrical liquid storage tanks resting on deformable foundations is developed in this work. The soil under the tanks is modeled as an elastic linear medium. The cylindrical wall is considered rigidly connected to the plate foundation. Here, concrete tanks are emphasized, although the study can be extended to other construction materials. For the analysis of the design forces acting on the tanks, efficient and simplified approximate expressions are derived based on rigorous analytical theories for thin shells and circular plate on elastic foundations. To verify the proposed approximate expressions and investigate the influence of the foundation deformability on displacements and design forces, parametric analyses of concrete tanks with different soil stiffness values are presented. The results illustrate the strong influence of the foundation stiffness on the tank design quantities and a very good performance of the simplified expressions.

Effect of the flow velocity on bubble boiling characteristics

The present research considers the initial stage of nucleate boiling with high heat fluxes releasing from the technical surface. We show new experimental data on the dynamics of the vapor phasein subcooled water flow in the channel under nonstationary heat release conditions. The heat release dissipation on the heater was performed by passing a controlled three–phase rectified electric current through a tube with a pulse duration of τimp = 60—300 ms with a heating rate of 1000—6000 K/s. We studied the formation dynamics and the structure of the vapor–liquid layer near the heat releasing wall and monitored the temperature state of the wall depending on the parameters of the heater’s flow and the intensity of heating of the cylindrical wall.

Numerical Investigation of Developing Natural Convection in Vertical Double-Passage Porous Annuli

The present study deals with the numerically investigation of developing laminar natural convection in the vertical double-passage porous annuli formed by three vertical concentric cylinders of which the middle cylinder is a thin and perfectly conductive known as baffle. In this analysis, two thermal conditions are considered namely, either inner or outer cylindrical wall is constantly heated while the opposite wall is insulated. An implicit finite difference technique is employed to solve the boundary layer equations in both the annular passages. The temperature profiles and velocity profiles in axial as well as radial directions have been presented for different values of Grashof number, Darcy number, baffle position and radius ratio. The results reveal that both physical and geometrical parameters have profound influence on the development of velocity and thermal fields as well as heat transfer rate.