Mitigation of Seismic Deformation of Anchored Quay Wall by Compacting

The anchored quay walls or bulkheads are commonly used in coastal areas. Previous studies on the seismic behavior of these quay walls have shown a significant effect of the liquefaction on the performance of the walls. Considerable length of an anchored sheet pile wall in Rajaii port, Iran, has been embedded in liquefiable sand. This study tries to clarify failure mechanism of the wall during earthquake and to identify more effective zone for improvement of the wall stability. Numerical modeling by DIANA software and physical modeling by shake table were presented. Results show that the main reason for extensive deformation of the system is the liquefaction of the soil adjacent to the root of the wall. The compaction of this zone improves the performance of the system and prevents large displacements. The mitigation plan was proven by comparison among the measured results, including the final shape, displacements and excess pore water pressure ratio

Mixed Convection Heat Transfer of Al2O3 Nanofluid on the Elliptical Shapes: Numerical Study of Irreversibility

In this study the 2D laminar and steady water-based Al2O3 nanofluid flow over a cylinder with circular, horizontal and vertical elliptical cross section by constant surface temperature boundary condition has been studied. The main goal of this research is to investigate the effects of different natural and mixed convection heat transfer mechanisms on the convective heat transfer coefficient, and the entropy generation due to the thermal and frictional origination. Conservation equations of the mass, momentum and energy under the assumption of incompressible, Newtonian nanofluid, by using the homogeneous single phase method have been solved. The impact of considered parameters in this study (alteration in cross section, convective flow direction and volume fraction of nano particles) in enhancing the heat transfer rate is studied in association with the entropy generated value in each case. Based on the results, the vertical elliptical cross section, in comparison with others, shows the highest entropy generation value and the heat transfer coefficient in all considered mechanisms. Moreover, mixed convection heat transfer type 2, in which the force flow is perpendicular to the buoyant flow direction, has the highest entropy generation and heat transfer rate for all cross sections. In addition, in all cases in the presence of the nanoparticles, the heat transfer rate and entropy generation increases

Experimental Study of Subcooled Boiling Heat Transfer of Axial and Swirling Flows inside Mini Annular Gaps

An experimental study of the subcooled boiling heat transfer of axial and swirling upward flows inside vertical mini annular gaps was conducted using deionized water. The subcooled boiling heat transfer coefficients and the boiling curves of the flow inside mini annular gaps with different gap sizes have been investigated. The experimental results both for the single phase heat transfer and subcooled boiling heat transfer inside mini annular gaps showed very good agreement with correlations in the literature. The results showed that the subcooled boiling heat transfer coefficient for a given heat flux increases as the size of the annular gap is decreased. The maximum wall superheat is also influenced negligibly by mass flux. Furthermore, the effects of swirl flow by using spring insets inside the mini annuli on the single phase and subcooled boiling heat transfer have been studied. The results showed that the single phase and subcooled boiling heat transfer coefficients are increased by having swirl flow inside mini annuli using spring inserts. The obtained results also showed that the heat transfer enhancement by having swirl flow inside the annuli using spring inserts decreases as the applied heat flux is increased in the subcooled boiling heat transfer region

Comparing the geodetical and geotechnical methods in investigating the deformation of earthfill dams; A case study of Mahabad Earthfill Dam, Iran

The monitoring of an earthfill dam during the various phases of the construction and service is a crucial process to investigate the performance of the dam from the safety point of view. Monitoring is carried out through installing the instruments at the critical locations. In the present paper, instrumentation data and the numerical analyses have been used for the monitoring of Mahabad earthfill dam, Iran. Numerical analyses were carried out using Plaxis and Sigma-W. Considering the good agreement between the measured data and the values predicted by Plaxis and Sigma-W, it can be concluded that the numerical models developed in the present paper are accurate enough to be used for the analysis of earthfill dams

PARAMETRIC STUDY OF OUTER-BRACE SCFS IN RIGHTANGLE TWO-PLANAR TUBULAR DKT-JOINTS OF OFFSHORE JACKET STRUCTURES

In the present paper, a set of parametric FE stress analyses is carried out for two-planar welded tubular DKT-joints under two different axial load cases. Analysis results are used to present general remarks on the effect of geometrical parameters on the stress concentration factors (SCFs) at the inner saddle, outer saddle, crown toe, and crown heel positions on the main (outer) brace. Based on the results of finite element analyses which are verified against the experimental data, a complete set of SCF database is constructed. Then a new set of SCF parametric equations is developed through nonlinear regression analysis for the fatigue design of two-planar DKT-joints under axial loads. An assessment study of these equations is conducted against the experimental data and the satisfaction of criteria regarding the acceptance of parametric equations is checked. Significant effort has been devoted by researchers to the study of SCFs in various uni-planar tubular connections. Nevertheless, for multi-planar joints covering the majority of practical applications, very few investigations have been reported due to the complexity and high cost involved

Flow structure and particle deposition analyses for optimization of a pressurized metered dose inhaler (pMDI) in a model of tracheobronchial airway.

Inhalation therapy plays an important role in management or treatment of respiratory diseases such asthma and chronic obstructive pulmonary diseases (COPDs). For decades, pressurized metered dose inhalers (pMDIs) have been the most popular and prescribed drug delivery devices for inhalation therapy. The main objectives of the present computational work are to study flow structure inside a pMDI, as well as transport and deposition of micron-sized particles in a model of human tracheobronchial airways and their dependence on inhalation air flow rate and characteristic pMDI parameters. The upper airway geometry, which includes the extrathoracic region, trachea, and bronchial airways up to the fourth generation in some branches, was constructed based on computed tomography (CT) images of an adult healthy female. Computational fluid dynamics (CFD) simulation was employed using the k-ω model with low-Reynolds number (LRN) corrections to accomplish the objectives. The deposition results of the present study were verified with the in vitro deposition data of our previous investigation on pulmonary drug delivery using a hollow replica of the same airway geometry as used for CFD modeling. It was found that the flow structure inside the pMDI and extrathoracic region strongly depends on inhalation flow rate and geometry of the inhaler. In addition, regional aerosol deposition patterns were investigated at four inhalation flow rates between 30 and 120 L/min and for 60 L/min yielding highest deposition fractions of 24.4% and 3.1% for the extrathoracic region (EX) and the trachea, respectively. It was also revealed that particle deposition was larger in the right branches of the bronchial airways (right lung) than the left branches (left lung) for all of the considered cases. Also, optimization of spray characteristics showed that the optimum values for initial spray velocity, spray cone angle and spray duration were 100 m/s, 10∘ and 0.1 sec, respectively. Moreover, spray cone angle, more than any other of the investigated pMDI parameters can change the deposition pattern of inhaled particles in the airway model. In conclusion, the present investigation provides a validated CFD model for particle deposition and new insights into the relevance of flow structure for deposition of pMDI-emitted pharmaceutical aerosols in the upper respiratory tract