Estimating the two-dimensional thermal environment generated by strong fire plumes in an urban utility tunnel

2021 ◽  
Vol 148 ◽  
pp. 737-750
Author(s):  
Kai Ye ◽  
Xiao Tang ◽  
Yuan Zheng ◽  
Xiaoyu Ju ◽  
Yang Peng ◽  
...  
Keyword(s):  
Thermal Environment ◽  
Two Dimensional ◽  
Fire Plumes ◽  
Utility Tunnel

A two-dimensional free vibration analysis of functionally graded sandwich beams under thermal environment

2012 ◽  
Vol 226 (12) ◽  
pp. 2860-2873 ◽  
Author(s):  
AR Setoodeh ◽  
M Ghorbanzadeh ◽  
P Malekzadeh
Keyword(s):  
Free Vibration ◽  
Shear Deformation ◽  
Vibration Analysis ◽  
Thermal Environment ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Geometrical Parameters ◽  
Sandwich Beams ◽  
Two Dimensional

In this article, free vibration analysis of elastically supported sandwich beams with functionally graded face sheets subjected to thermal environment is presented. In order to accurately include the transverse shear deformation and the inertia effects, two-dimensional elasticity theory is used to formulate the problem. The layerwise theory in conjunction with the differential quadrature method is employed to discretize the governing equations in the thickness and axial directions, respectively. The material properties of functionally graded face sheets are assumed to be temperature-dependent and graded in the thickness direction according to a power-law distribution. For the purpose of comparison, the problem under consideration is also solved using two-dimensional finite element method and the first-order shear deformation theory. The accuracy, convergence, and versatility of the method are demonstrated by comparing the results with those of the two aforementioned approaches and also with the existing solutions in literature. Eventually, some new numerical results are presented which depict the effects of different material and geometrical parameters on natural frequencies and mode shapes of the beam.

Effect of In-Plane Load and Thermal Environment on Buckling and Vibration Behavior of Two-Dimensional Functionally Graded Tapered Timoshenko Nanobeam

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Roshan Lal ◽  
Chinika Dangi
Keyword(s):  
Thermal Environment ◽  
Slenderness Ratio ◽  
Differential Quadrature Method ◽  
Equations Of Motion ◽  
Nonlocal Parameter ◽  
Beam Theory ◽  
Functionally Graded ◽  
Two Dimensional ◽  
Power Law Distribution ◽  
Energy Principle

Abstract In this work, buckling and vibration characteristics of two-dimensional functionally graded (FG) nanobeam of nonuniform thickness subjected to in-plane and thermal loads have been analyzed within the frame work of Timoshenko beam theory. The beam is tapered by linear variation in thickness along the length. The temperature-dependent material properties of the beam are varying along thickness and length as per a power-law distribution and exponential function, respectively. The analysis has been presented using Eringen’s nonlocal theory to incorporate the size effect. Hamilton’s energy principle has been used to formulate the governing equations of motion. These resulting equations have been solved via generalized differential quadrature method (GDQM) for three combinations of clamped and simply supported boundary conditions. The effect of in-plane load together with temperature variation, nonuniformity parameter, gradient indices, nonlocal parameter, and slenderness ratio on the natural frequencies is illustrated for the first three modes of vibration. The critical buckling loads in compression have been computed by putting the frequencies equal to zero. A significant contribution of in-plane load on mechanical behavior of two-directional functionally graded nanobeam with nonuniform cross section has been noticed. Results are in good accordance.

scholarly journals Optimal Heat Distribution Using Asymptotic Analysis Techniques

2021 ◽  
Author(s):  
Zakaria Belhachmi ◽  
Amel Ben Abda ◽  
Belhassen Meftahi ◽  
Houcine Meftahi
Keyword(s):  
Asymptotic Expansion ◽  
Heat Source ◽  
Asymptotic Analysis ◽  
Numerical Experiments ◽  
Thermal Environment ◽  
Topological Derivative ◽  
Maximum Temperature ◽  
Heat Distribution ◽  
Two Dimensional ◽  
Optimal Heat

In this chapter, we consider the optimization problem of a heat distribution on a bounded domain Ω containing a heat source at an unknown location ω⊂Ω. More precisely, we are interested in the best location of ω allowing a suitable thermal environment. For this propose, we consider the minimization of the maximum temperature and its L2 mean oscillations. We extend the notion of topological derivative to the case of local coated perturbation and we perform the asymptotic expansion of the considered shape functionals. In order to reconstruct the location of ω, we propose a one-shot algorithm based on the topological derivative. Finally, we present some numerical experiments in two dimensional case, showing the efficiency of the proposed method.

Numerical Simulation of the Aerodynamics and Aerothermal Heating for a Hypersonic Vehicle

2012 ◽  
Vol 429 ◽  
pp. 147-153
Author(s):  
Hai Yong Liu ◽  
Hong Fu Qiang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mach Number ◽  
Thermal Environment ◽  
Three Dimensional ◽  
Hypersonic Vehicle ◽  
Attack Angle ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model

A hypersonic forebody based on waverider and liftbody concept was presented. The configuration of a new hypersonic vehicle was designed by taking the configuration of X43A. Numerical simulation was conducted on the two-dimensional and three-dimensional models of the vehicle using CFD software of Gambit and Fluent. The effects of Mach number and attack angle on the aerodynamics and heat transfer were considered. The results of simulation investigation showed that: High compressed air was constrained beneath the pre-compressed surface of the forebody. The computational data on central cross section of the three-dimensional model for the vehicle was similar to that of the two-dimensional model. But great pressure gradient existed between the pre-compressed surface and side surface of the forebody which would lead to severe air leakage and pressure loss. The increasing of attack angle and Mach number enforced the stagnation of shock wave on the side walls of the engine. The thermal environment of the vehicle was deteriorated rapidly with increasing Mach number. But the viscous heating was overrated which lead to unbelievable high temperature. The software Fluent was more suitable to predict the aerodynamics than the heat transfer for hypersonic flow.

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