Surface aeration experiments were conducted in two types of Rectangular tanks of aspect ratios i.e., length to width ratio (L/W) of 1.5 and 2 and developed simulation equations to correlate the oxygen transfer coefficient, k and power number, P0 with a parameter governing theoretical power per unit volume X. The parameter X is defined as equal to F4/3R1/3, where F and R are impellers’ Froude and Reynolds numbers respectively). Results have shown that the P0 can not be simulated singularly with either Reynolds number, R or Froude number, F, which results in scale effects; there appears to be a need to incorporate the effects of both F and R. It was found that P0 is uniquely related to X for Rectangular aeration tanks of both aspect ratios, however, such relationships are different depending upon the aspect ratios. It has been demonstrated that energy can be saved substantially if the aeration tanks are run at relatively higher input powers. It is also demonstrated that smaller sized tanks are more energy conservative and economical when compared to big sized tanks, while aerating the same volume of water, and at the same time by maintaining a constant input power in all the tanks irrespective of their size.      

In this study, the damping effect of the horizontal baffles inside a liquid storage tank is investigated. For this purpose, a numerical model based on the finite volume method is established. The numerical model is used to evaluate the accuracy of the analytical model developed to estimate the hydrodynamic damping caused by wall bounded baffles. For this purpose, several full-scale baffled tanks with different aspect ratios are numerically analyzed, and the validity of the analytical model is discussed with respect to the numerical results. Next, the reduction in sloshing wave height due to the presence of the baffles is considered for selected tanks subjected to seismic excitations. Finally, a simple procedure to seismically evaluate the reduction of sloshing amplitude due to the presence of baffles is proposed and validated using the time history numerical results.

Many liquid storage tanks around the world have affected by earthquakes. This structure can store dangerous chemical liquids. Hence dynamic behavior of ground supported Rectangular storage tanks is very important due to their applications in industrial facilities. In current research, the seismic behavior of two water storage Rectangular concrete tanks is examined. For this purpose, these tanks are modeled in FEM software for analyzing. These tanks are analyzed under four type of analysis: static, modal, response-spectrum and time-history analysis. Time history analysis can take all the nonlinear factors into the analysis, so it is used to estimate the exact amount of structural response. In time history analysis, earthquake accelerograms of Tabas, Kobe and Cape Mendocino have been applied to tanks. Finally, it is resulted that Displacement, base shear and wave height obtained from time history analysis are more than those of response spectrum analysis, indicating insufficiency of response spectrum analysis. In time history analysis, the maximum displacement is achieved in highest part of the tanks. It is due to the wave height which created in earthquake. By increasing in dimension, the wave height is also increased.

Sloshing Wave Impact Force (SWIF) caused by liquid motion during seismic excitations is investigated in this paper. When the freeboard is insufficient, the liquid waves collide to the tank roof on which uplift forces are produced. Due to the complication of sloshing impaction, there is no comprehensive investigation that can clarify the various aspect of this phenomenon. Therefore, most of standards don’t recommend any method to evaluate SWIF. Alternatively, the main approach of related codes and standards is to suggest a required freeboard in order to prevent collision of sloshing wave to the tank roof instead of evaluating the SWIF. However, suggested freeboard is too high to meet economic considerations in some cases.Therefore, the impact forces should be reasonably evaluated based on the experimental measurements and analytical solutions. An experimental investigation has been implemented to clarify the influence of various geometrical parameters on the impact roof pressure and force values of a Rectangular tank. A series of shaking table tests are conducted for a partially filled Rectangular tank under harmonic and different earthquake excitations. The experimental measurements for SWIF are compared with those recommended by code provisions and the effects of various parameters on SWIF are discussed.

In primary sedimentation tanks, short-circuiting enlargement of dead zones and high flow mixing problems are caused by circulation regions (dead zones), which can reduce the optimal sedimentation of particles. For proper design of such tanks, the formation of recirculation zones should be avoided. The provision of a baffle as a geometrical medication of a tank may influence the flow field for better sedimentation. Thus, in this study, velocity measurements were performed by a three-dimensional Acoustic Doppler Velocimeter (ADV) to investigate baffle effects on the velocity distribution in a primary Rectangular sedimentation tank, quantitatively. Effects of baffle positioning were also determined. Mean flow analysis shows how a baffle can alter the hydrodynamics of the flow field. It was quantitatively found that the intermediate baffle not only influences the flow field in its downstream, but also affects the flow pattern in its upstream. It was found that the baffle setting and its position relative to the inlet and outlet influences the flow field and the development of flow. Baffled flow may provide better conditions for sedimentation by influencing velocity profiles. However, further detailed experimental study is necessary to fully capture the baffle effect and obtain further insight into the complex flow field in a sedimentation tank.

Liquid sloshing is a common phenomenon in transporting liquid tanks. Liquid waves lead to fluctuating forces on the tank wall. If the fluctuations are not predicted or controlled, they can lead to large forces and momentum. Baffles can control liquid sloshing fluctuations. One numerical method, widely used to model the liquid sloshing phenomena, is Smoothed Particle Hydrodynamics (SPH). Because of its Lagrangian nature, SPH is suitable for simulating free surface flow. In the present study, a relatively accurate Incompressible SPH (ISPH) method is improved by kernel gradient correction tensors, particle shifting algorithms, turbulence viscosity calculations, and free surface particle detectors is applied for the free surface flow modeling. In comparison to the other SPH simulations and experimental data, the results show that the present algorithm is effective for simulating free surface problems. The present algorithm is applied to simulate liquid sloshing phenomena, while the aim of this study is the investigation of vertical and horizontal baffle effects on the control and damping of liquid sloshing. Results show that, baffle size has a major role in sloshing fluctuation damping for vertical baffles. For horizontal baffles, also including size, the baffle base position has a significant role in liquid sloshing fluctuation damping. When horizontal baffle is near the free surface, sloshing fluctuation-damping increases.