One of the main challenges associated with the development of irrigation systems and other water distribution systems is the sediment removal from the inlet channel. Vortex settling basin (VSB) is one of the types of sediment extractors with small size and high efficiency which removes the sediments using the vortices of the flow. Studies on the proper design of VSBs are generally based on experimental and physical models which are highly costly and time-consuming. In this study, SSIIM model was evaluated for the simulation of flow field and sediment distribution in a VSB and the results were compared with experimental measurements. After ensuring the relative agreement of the model results with experimental measurements, the effect of different design parameters such as inlet sediment size, bottom outlet discharge ratio, and bed level difference between inlet and outlet channels were investigated. The results showed that among the design parameters, trap efficiency of the VSB is more sensitive to the sediment size. By increasing the bottom discharge ratio, the efficiency increases, but this increase in the efficiency barely exceed 4 % for bottom discharge ratios higher than 10 %. In addition, increasing the bed elevation difference between the inlet and outlet channels can increase the efficiency up to 18 % for fine-grained sediments, while this increase is less than 10 % for coarse-grained sediments.

The study on the flow behave inside of a ball valve is important for heavy crude oil transportation. Owe to the fast progress of the numerical technique, it becomes an effective way to observe the flows inside a valve and to analyze the flow structure of the oil-water core annular flow. In the present study, the simulation of the oil-water core annular flowing through the valve is conducted by combined the VOF and CSF model, and the effects of open rate on vortex and oil distribution characteristics are analyzed. The simulated data is a satisfactory match with empirical value and the experimental results. The results show that there are lots of vortexes inside and behind the valve, the coordinate values of the vortex decrease and the aggregation rate increases with increase in open rate. As the input velocity increases, the change rate of the vortex position is greater, and the oil aggregation rate decreases, the highly viscous oil with has greater aggregation rate after flow through the valve, and the variation of the vortex core position is relatively slow. As the vortex flow across the oil core, the oil will be scattered and contributes to the instability of the annular flow.

One of the obvious reasons for most disorders in network service provisioning is network path congestion. Congestion avoidance in today's networks is too costly and sometimes impossible. With the introduction of SDN, centralizing the equipment's control plane has become possible. This paper presents an enhanced method named ESV-DBRA to avoid congestion in multi-tenant SDN networks. At first, ESV-DBRA monitors the traffic load and delay of all network paths for each tenant individually. Then, by merging the parameters obtained from the monitoring, the Service Level Agreements (SLA), and a novel proposed cost function, it calculates the cost of the network paths per tenant. As a result, traffic for each tenant is routed through the path/paths at the lowest possible cost from the tenant's perspective. Next, the bandwidth quotas will be calculated and assigned to the tenants over their optimal routes. Afterward, whenever congestion is likely to occur in a path, ESV-DBRA automatically changes the route or bandwidth of the tenants' traffic related to this path to avoid congestion. Related algorithms are also proposed.Eventually, simulations show that the proposed method effectively increases bandwidth utilization by 10.76%.

Different types of contact, including contact between node pairs, any-contact of nodes, and contacts of the entire network, are used to characterize social relations in mobile social networks. Different modes of routing, from the point of view of message delivery semantics, encompass unicasting, multicasting, any-casting, and broadcasting. Studies have shown that using probability distribution functions of contact data, which is mainly assumed to be homogeneous for nodes, improves the performance of these networks. However, there exists an important challenge in studies on distributions. A lot of works apply the distribution of one type of contact to other types. Hence in routing applications, it causes to use of the distribution of one type of contact for any mode of routing. This study provides a complete solution to model each type of homogeneous contact data distribution and to use them in different modes of routing. We propose a routing algorithm that uses this new model. Results show that our solution improves the average latency of comparing methods Epidemic, TCCB, and DR about 3.5-times, 30%, and 45%, respectively. It achieves a delivery rate of about 5% and 6%, and average latency about 6% and 8% better than that of DR and TCCB, respectively.

Annular vortex tube is a vortex tube which allows the hot flow pass again over the hot tube. It is introduced for first time in this work. Hot Flow is not allowed to exit after passing conic valve in annular vortex tube, but it is redirected over hot tube. This back flow absorbs heat from outer wall of hot tube. To study temperature separation which occurs in an annular vortex tube; the performance of this type of vortex tube has been experimentally tested and compared with the performance of a typical vortex tube. Inlet test pressure is 4 bars and natural gas is being used as working fluid. For both type of vortex tubes, ratio of length to diameter of tube is 10. Cold oriice diameter of vortex generator is set to 6.4 mm. It was observed that redirecting hot flow over the hot tube in annular vortex tube improves cooling efficiency up to 24% respect to a typical vortex tube at the maximum temperature difference. The results show that cold mass fraction in which the coldest temperature occurs is lower for annular vortex tube comparing with a typical vortex tube.

Monitoring and evaluation of transformers are essential to prevent their insulation failure. In this paper, the use of 2-furan-carboxaldehyde (2-FAL) and methanol (MeOH) concentrations as the main products of paper insulation degradation, and insulation condition markers, has been studied. In order to study the degradation process and production of degradation products, the thermal aging process of the transformer insulation system was implemented in laboratory conditions. The results of laboratory studies show that in the early stages of degradation the amount of MeOH is significant compared to 2-FAL. Also, the estimation of the degree of polymerization (DP) in the early stages of degradation (DP>800) through MeOH concentration and with decreasing DP (DP <800) through 2-FAL concentration is closer to the real value. The results of studies performed on 35 distribution transformers confirm the production of significant amounts of MeOH in the early stages of degradation. Also, the estimated DP values for the studied transformers were obtained through 2-FAL and MeOH concentration. The results show that estimating the amount of DP through MeOH concentration is associated with a probability of error of about 9% compared to estimating DP through 2-FAL concentration.

For a long time, many efforts have been taken on improving gas turbine performance to increase the propulsive force and keep the chamber walls cool. In this regard, implementation of cyclonic and vortex engines have been proposed. According to increasing in the engine efficiency and keeping the chamber walls cool, the bidirectional vortex flow which is exited in the vortex engine, makes researchers more interested in it. In the vortex engine, due to its specific geometry, two vortex layers are established. The combustion occurs in the inner vortex layer, while the outer layer protects the walls from excessive heat transfer. The vortex engine with gas fuel and oxidizer has been manufactured in laboratory scale at Virginia Institute of Technology and it is under investigation. Practical usage of the vortex engine, with both liquid and solid fuels, has its own significance. Investigation and analysis of the flow field in such a chamber have been conducted in different research centers during last five years. The significant results of these studies are the analytical and numerical solution of the flow field by applying many simplifying assumptions. Selecting proper materials, determining the engine dimensions, designing injector plate, and some other parameters in engine manufacturing process require the flow field to be modeled in the combustion chamber which needs the governing equations to be solved. For investigating of the flow field in the vortex engine, the mass conservation, momentum conservation, and energy equations have to be solved. If the flow is turbulent, the equations become more complicated and many assumptions are needed to simplify the problem. Note that, by assuming the flow to be incompressible, the energy equation becomes segregated from the other equations. At the first stage, the goal of this project is to investigate the previous analytical solution and modify it to become compatible with other numerical and experimental results, provide numerical solution of the governing equations with the least possible assumptions, and compare the obtained numerical and analytical results with each other. Since the governing equations are non-linear and the flow is turbulent, it is impossible to solve the problem analytically in details. The flow will be simulated with respect to the result of numerical solution and applying the conventional methods and the results will be presented. It is to be noted that, if the fuel is liquid, modeling the spray combustion in a two-phase (gas-liquid) flow field is required, which will be described in this project as well. According to the flow field analysis, the propulsive and aero-dynamical results of the engine will be available, which are required to determine the designation parameters and manufacturing of the vortex engine test rig. Afterwards, by establishing the fundamental requirements for installing the appropriate test rig for the vortex engine, manufacturing of this test rig with its accessories will be described in details. The obtained results of this project, including the flow field investigation, test rig designation and implementation, are the first steps to achieve mass production of the vortex engine with both liquid and gas fuels which, according to its innovation and efficiency, has its own significance.

To investigate the dynamics of droplet-vortex interactions in particle-laden Karman vortex street flows, the simulations were carried out by using Euler-Lagrange approach, which was validated by the available experiments and numerical results. Then, the particle dispersion and the dimensionless frequency (Strouhal number) of the wake flow were analyzed to evaluate the particle-vortex interactions. The particle dispersion was statistically analyzed from both time and space dimensions and the different instantaneous dispersion patterns were explained by the relative slip velocity. Two independent scaling parameters, Stokes number StL and particle-fluid mass loading ratio Φ were revealed, and the particle mean square displacement and the Strouhal number were modelled by using these two scaling parameters, respectively. Finally, the characteristic lengths of the particle-laden wake flow were researched, and the Strouhal number physical model was developed based on the oscillating fishtail model. The results indicated that, firstly, StL and Φ, which constitute a dominant scaling group, can characterize the dynamics of droplet-vortex interactions in wake flow. Particles gradually separate from the vortex with the increase of StL due to the centrifugal effect, and the vortex intensity and regularity get worse with the increase of Φ, which further disperses the droplets for their momentum exchange with irregular vortex structures. Secondly, the length of the formation region and the width of the free shear layer diffuse are the two simultaneous characteristic lengths of the Strouhal number in oscillating wake. The proposed Strouhal number model gives a physical basis for the frequency determination, and the predicted errors are within ±1. 5% error bands with mean absolute percentage error of 0. 67%.

Vortex extrusion (VE) is a new severe plastic deformation method that simultaneous reduction in area and twisting around the longitudinal axis of the workpiece, within the fixed convergent die, leads to the accumulation of high amounts of strain on the sample. Due to the many capabilities of this process such as creating high strain in a pass, simplicity and no need for complex equipment and homogeneity of strain distribution, in this paper, the simultaneous effect of reduction in area, twist angle and curvature of slip lines on the mean effective strain, maximum damage factor and the steady state load of the process were investigated. The results showed that the mean effective strain value increased with increasing reduction in area and twist angle and there is a significant interaction between mentioned factors. The maximum damage factor was observed at the surface of work piece, which according to the values of positive mean stress in these points it can be said that the possible initiated cracks propagate under tensile state of stress. Reduction in area and twist angle are the effective factors on steady state load of process but the curvature of the slip lines does not have much effect on it. Maximum of damage factor was determined for VE die with curved streamlines, reduction in area equal to 30% and twist angle of 30 degree.