In this paper, BUBBLE FORMATION process has been studied numerically by entering air into a submerged orifice placed in a cylinder. The SOLA-VOF method was used to simulate the BUBBLE FORMATION. In This code, complete form of Navier-stocks equations was predicted two dimension and using finite difference method. Also in this study, the effect of air flow rate on the BUBBLE size and its FORMATION time at very low rates was studied.

Two-phase flow systems analysis data are rear and cause major problems as efficient prediction in operation and control of the system or delay in identifying system parameters behavior. Analysis of the pressure waves through transient conditions can be an effective method to achieve precise results. In the present article, the BUBBLE FORMATION was studied using computational fluid dynamics (CFD) and the acoustic finite element method (FEM). The simulation conducted to obtain the aerodynamic noises generated by initiation and separation of BUBBLEs in a vertical column. A Transient three-dimensional model is developed based on VOF method for tracking interface of two phases and large eddy simulation (LES) for an accurate calculation of pressure fluctuations. The model is simulated with the aid of the commercial software ANSYS FLUENT based on the finite volume method. To obtain convergence the implicit body force treatment is taken into account PISO algorithm is used to calculate a consistent result between velocity and pressure field. Pressure is discretized with PRESTO scheme. The RANS solution is used to calculate the initial flow field. In this case momentum is discretized with the second order upwind scheme and the geometric reconstruction scheme has been used as the volume fraction discretization scheme. Due to the importance of interface tracking in sound sources recognition and the problems which occur during adding LES model in the simulation, different interface reconstruction methods has been compared. High Resolution Interface Capturing scheme (HRIC) is selected as the best method. The Fofwcs Williams and Hawking (FWH) equation is used as an extension of the classical Lighthill aerodynamic acoustics for predicting far field noises. Sound sources are extracted by taking samples of pressure fluctuations from Wall penetration and virtual plane that is defined parallel to flow. These sources are investigated in the moment of separation and FORMATION of BUBBLE. In this paper are concluded that the largest fluctuation occur during necking of BUBBLEs, while the smallest BUBBLE produced the biggest peak in acoustic fluctuation curves. Besides time analysis, the pressure fluctuation is transferred from time domain to frequency by Fourier transform method and spectral analysis is performed on the data. The spectral analysis are compared to experimental results to better understand the effects of turbulence models, flow rate and methods of taking sample on the acoustic frequency response. The spectra of the filtered acoustic data (at airflow rate of 240 lit/min) shows a peak at about 40 Hz and is shown frequency response increases by the decrement of flow rate in bubbly flow. In this research frequency merge of two BUBBLEs is demonstrated at 800 Hz and frequency response is used to estimate the BUBBLE size.

Laser Doppler Velocimetry (LDV) has been employed to determine pseudo-turbulence characteristics of the flow field around BUBBLE train forming in non-Newtonian caboxymethylcellulose (CMC) aqueous solution at low gas flow rate condition. The Reynolds stress and turbulent intensity of the liquid were investigated by means of Reynolds time-averaged method. The experimental results show that axial Reynolds stress rises greatly and then fluctuates slightly with the vertical height, whereas displays symmetrical Gaussian distribution in the horizontal direction; Radial Reynolds stress changes nonobviously in the vertical direction, but increases followed by a decrease in the horizontal direction. The axial turbulent intensity begins to wave to some degree with the height for near vertical axis passing through orifice center, but maintains constant within BUBBLE channel in the horizontal direction; Radial turbulent intensity gets down with the vertical height, compared with the opposite trend of its variation with the horizontal distance.

Analyzing the FORMATION of BUBBLE prices in stock market is the most important macro subjects in recent years. Due to this, in this paper we use a DSGE model (developed by Castelnuovo and Nisticò, , 2010) in order to study BUBBLEs in stock market price index. Because the price BUBBLE is a non-fundamental factor, using the approach of separating fundamental from non-fundamental factors is a good way to evaluate the FORMATION of the BUBBLE in the stock market. Accordingly, in this paper, the variables of changes in inflation, production and stock price are divided into fundamental and non-fundamental factors and then investigated the effect of nonfundamental shocks on macro variables such as stock price and stock price BUBBLE FORMATION. By calibrating the model, the results show that non-fundamental factors hidden in inflation, production and stock prices cause the FORMATION of BUBBLEs in the stock market. Also, among the above factors, non-fundamental inflation factors are the most important factor in the FORMATION of the stock price BUBBLE, and then fluctuations in the production sector and the stock price itself. The results show the stability in the stock market and avoiding the FORMATION of BUBBLEs in the stock price index mainly depends on controlling inflation rate and general prices level.

In this study, an attempt has been made to investigate the impact of psychological factors on the fluctuations of coin prices in the market. Psychological factors belong to a category of factors that have given rise to the subfield of behavioral economics. On the other hand, price fluctuations near certain numbers, are an example of market inefiiciency, which contradicts the foundation of classical economic theories. The period under study in this research ranges from 1392 to 1400, including a period of price stability (1392-1396) and a priodof high fluctuations due to international sanctions(1396-1400). The price range during this period has been from 800000 Tomans to 16000000 Tomans.The GARCH (Generalized Autoregressive Conditional Heteroskedasticity) approach is used to estimate the corresponding equation. Here, a 10-day period is considered, and four time intervals around the barriers are examined. To further investigate the hypotheses and the distribution of prices around random numbers, the Nikooyi fitting method is used. The research results confirm the existence of price clustering phenomenon for coins during the period of 1396-1400. The results indicate that the dispersion of numbers in prices is not uniform, and prices show reactions to random numbers. On the other hand, the existence of this psychological phenomenon leads to the creation of a coin BUBBLE or the deviation of coin prices from the equivalent price of 10 grams of gold, which is considered as the real and intrinsic value of the coin. In bullish market conditions, the coin BUBBLE is more significant, but in bearish and stable market conditions, this BUBBLE decreases."

Digital Image Analysis (DIA) has been employed to characterize the time evolution of a BUBBLE injected from a single orifice into a pseudo 2-dimensional gas-solid fluidized bed. The injected BUBBLE diameter increased with the square root of time before detachment. During BUBBLE free flight in the bed, its diameter remains approximately constant. The center of mass of the BUBBLE increases with the second power of the time. The results show that the classical models for BUBBLE injection can predict the time evolution of BUBBLE diameter, and its center of mass. BUBBLE tends to elongate during injection and after detachment its height to width aspect ratio decreases. Image analyzing results were also used for the study of gas leakage from the BUBBLE to emulsion phase, and it has been shown that the dense phase expands up to 1.04 times the minimum fluidization condition for large BUBBLEs. The expansion ratio of the dense phase increases linearly with BUBBLE diameter.

The present study aims to design an early warning model to investigate the effect of OPEC summit announcements on the FORMATION of BUBBLEs in the Iranian stock market. To identify BUBBLEs between April 2012 and February 2023, the Generalized Supremum Augmented Dickey-Fuller (GSADF) test was applied. After detecting BUBBLE periods, a predictive model was developed using probit regression. The results indicate that the early warning model achieves 94% accuracy in predicting BUBBLE periods in the Iranian stock market. Moreover, OPEC summit announcements to reduce (maintain) production levels are associated with a lower (higher) probability of BUBBLE FORMATION. Announcements to maintain production levels create optimistic expectations that raise the future expected value of stocks beyond what fundamental economic factors suggest, thereby increasing the likelihood of a price BUBBLE. Overall, the findings confirm that the Iranian stock market is significantly influenced by OPEC summit announcements.