This paper deals with the thermal analysis of reptiles and pelycosaurs. The energy budgets affect... more This paper deals with the thermal analysis of reptiles and pelycosaurs. The energy budgets affecting the body temperature of the reptile are presented. In the analysis the behaviour of the reptile, energy gains and losses due to metabolism, evaporation, solar heat, convection, and radiation are considered. The effect of the sail of pelycosaurs is also examined. Finite difference equations are
... Designers introduced plans from the west, which were used in industrialised societies. These ... more ... Designers introduced plans from the west, which were used in industrialised societies. These designs have been applied to the Cypriot environment with no changes to fit the social or climatic conditions, losing the comfort offered by the traditional house environment. ...
This paper examines the application of CFD modelling to simulate the complex multiphase character... more This paper examines the application of CFD modelling to simulate the complex multiphase characteristics inside a wickless heat pipe (thermosyphon). Water and refrigerant R134a were selected as working fluids. A novel and comprehensive three-dimensional CFD model of a wickless heat pipe was developed to simulate both the complex multiphase heat and mass transfer characteristics of boiling and condensation and the heat transfer characteristics of the cooling fluid in the condenser e heat exchanger. The CFD simulation has successfully predicted, for the first time, a boiling regime and two phase flow pattern that takes place with water at low power throughput, known as geyser boiling. The effects of the power throughput on the characteristics of the geyser boiling were investigated. The CFD simulation was also successful in modelling and visualising the multiphase flow characteristics, emphasising the difference in pool boiling behaviour between these working fluids. Temperature profiles and visual validation of the resulting 3D CDF findings were conducted using two experimental facilities.
... Wrobel and Brebbia [24] developed an efficient Newton-Raphson scheme and implemented it in co... more ... Wrobel and Brebbia [24] developed an efficient Newton-Raphson scheme and implemented it in conjunction with a ... Defining where Ta is the ambient temperature, the equation in terms of the new variable becomes = a ... 160 ADVANCES IN NUMERICAL HEAT TRANSFER, VOL. ...
The analysis of cracked brittle mechanical components considering linear elastic fracture mechani... more The analysis of cracked brittle mechanical components considering linear elastic fracture mechanics is usually reduced to the evaluation of stress intensity factors (SIFs). The SIF calculation can be carried out experimentally, theoretically or numerically. Each methodology has its own advantages but the use of numerical methods has become very popular. Several schemes for numerical SIF calculations have been developed, the J-integral method being one of the most widely used because of its energy-like formulation. Additionally, some variations of the J-integral method, such as displacement-based methods, are also becoming popular due to their simplicity. In this work, a simple displacement-based scheme is proposed to calculate SIFs, and its performance is compared with contour integrals. These schemes are all implemented with the Boundary Element Method (BEM) in order to exploit its advantages in crack growth modelling. Some simple examples are solved with the BEM and the calculated...
An adaptive boundary element scheme is developed using the concept of local reanalysis and quadra... more An adaptive boundary element scheme is developed using the concept of local reanalysis and quadratic h-hierarchical functions for the construction of near optimal computational models. The use of local reanalysis in the error estimation guarantees the reliability of the modeling process while the use of h-hierarchical elements guarantees the efficiency of the adaptive algorithm. The technique is developed for the elastic analysis of two-dimensional models. A practical example of a microstructure component shows the rapid convergence of the results with few refinement steps.
This paper deals with the thermal analysis of reptiles and pelycosaurs. The energy budgets affect... more This paper deals with the thermal analysis of reptiles and pelycosaurs. The energy budgets affecting the body temperature of the reptile are presented. In the analysis the behaviour of the reptile, energy gains and losses due to metabolism, evaporation, solar heat, convection, and radiation are considered. The effect of the sail of pelycosaurs is also examined. Finite difference equations are
... Designers introduced plans from the west, which were used in industrialised societies. These ... more ... Designers introduced plans from the west, which were used in industrialised societies. These designs have been applied to the Cypriot environment with no changes to fit the social or climatic conditions, losing the comfort offered by the traditional house environment. ...
This paper examines the application of CFD modelling to simulate the complex multiphase character... more This paper examines the application of CFD modelling to simulate the complex multiphase characteristics inside a wickless heat pipe (thermosyphon). Water and refrigerant R134a were selected as working fluids. A novel and comprehensive three-dimensional CFD model of a wickless heat pipe was developed to simulate both the complex multiphase heat and mass transfer characteristics of boiling and condensation and the heat transfer characteristics of the cooling fluid in the condenser e heat exchanger. The CFD simulation has successfully predicted, for the first time, a boiling regime and two phase flow pattern that takes place with water at low power throughput, known as geyser boiling. The effects of the power throughput on the characteristics of the geyser boiling were investigated. The CFD simulation was also successful in modelling and visualising the multiphase flow characteristics, emphasising the difference in pool boiling behaviour between these working fluids. Temperature profiles and visual validation of the resulting 3D CDF findings were conducted using two experimental facilities.
... Wrobel and Brebbia [24] developed an efficient Newton-Raphson scheme and implemented it in co... more ... Wrobel and Brebbia [24] developed an efficient Newton-Raphson scheme and implemented it in conjunction with a ... Defining where Ta is the ambient temperature, the equation in terms of the new variable becomes = a ... 160 ADVANCES IN NUMERICAL HEAT TRANSFER, VOL. ...
The analysis of cracked brittle mechanical components considering linear elastic fracture mechani... more The analysis of cracked brittle mechanical components considering linear elastic fracture mechanics is usually reduced to the evaluation of stress intensity factors (SIFs). The SIF calculation can be carried out experimentally, theoretically or numerically. Each methodology has its own advantages but the use of numerical methods has become very popular. Several schemes for numerical SIF calculations have been developed, the J-integral method being one of the most widely used because of its energy-like formulation. Additionally, some variations of the J-integral method, such as displacement-based methods, are also becoming popular due to their simplicity. In this work, a simple displacement-based scheme is proposed to calculate SIFs, and its performance is compared with contour integrals. These schemes are all implemented with the Boundary Element Method (BEM) in order to exploit its advantages in crack growth modelling. Some simple examples are solved with the BEM and the calculated...
An adaptive boundary element scheme is developed using the concept of local reanalysis and quadra... more An adaptive boundary element scheme is developed using the concept of local reanalysis and quadratic h-hierarchical functions for the construction of near optimal computational models. The use of local reanalysis in the error estimation guarantees the reliability of the modeling process while the use of h-hierarchical elements guarantees the efficiency of the adaptive algorithm. The technique is developed for the elastic analysis of two-dimensional models. A practical example of a microstructure component shows the rapid convergence of the results with few refinement steps.
Uploads
Papers by Luiz Wrobel