Figure 1: Left: fluid flowing around a cylinder with no-slip boundary condition in two dimensions. Right: dam break of fluid flowing around rotating cylinders with no-slip boundary condition in three dimensions.
AbstractSimulating solid-fluid coupling with the classical meshless methods is an difficult issue due to the lack of the Kronecker delta property of the shape functions when enforcing the essential boundary conditions. In this work, we present a novel staggered meshless method to overcome this problem. We create a set of staggered particles from the original particles in each time step by mapping the mass and momentum onto these staggered particles, aiming to stagger the velocity field from the pressure field. Based on this arrangement, an new approximate projection method is proposed to enforce divergence-free on the fluid velocity with compatible boundary conditions. In the simulations, the method handles the fluid and solid in a unified meshless manner and generalizes the formulations for computing the viscous and pressure forces. To enhance the robustness of the algorithm, we further propose a new framework to handle the degeneration case in the solid-fluid coupling, which guarantees stability of the simulation. The proposed method offers the benefit that various slip boundary conditions can be easily implemented. Besides, explicit collision handling for the fluid and solid is avoided. The method is easy to implement and can be extended from the standard SPH algorithm in a straightforward manner. The paper also illustrates both one-way and two-way couplings of the fluids and rigid bodies using several test cases in two and three dimensions.
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AbstractRe-injection of produced gas is a common strategy to maintain pressure and to meet environmental regulations in gas condensate reservoirs and also to store gas until the market available. Although the best idea to prevent liquid loss is the full pressure maintenance development above the dew point pressure, the partial pressure maintenance process below dew point may be desirable for economic reasons, as the dew point pressures in some gas condensate reservoirs discovered in recent years is very high. In this case one major concern is whether gas cycling above the dewpoint is more profitable than below the dewpoint. Therefore, a knowledge of accurate condensate recoveries under two different development schemes is vital for making the accurate economic assessment and making final decisions.To the end, a series of experiments have been done to investigate the condensate recovery based on the above two different development strategies and quantitatively determine the revaporization efficiency of retrograde condensate by lean gas injection. First the gas injection below the dewpoint was performed in a long-core apparatus. In order to calculate the quantitative amount of the revaporized condensate, other two parallel tests of gas injection above the dew point in a long core system and gas injection below the dew point in the PVT cell were conducted as a comparative basis. The actual gas condensate fluid and a long core system are employed here. The gas condensate used is rich and highly waxy. As a complete study, the routine phase behavior is first detailed, including constant mass expansion and constant volume depletion. An interesting finding in PVT cell shows that lean gas can not only effectively revaporize the intermediate but also C 20 plus components. Comparison of the tests in longcore system illustrates that more condensate above the dewpoint is recovered than below the dewpoint. This is consistent with the conventional idea that the full pressure maintenance is superior to the partial pressure maintenance according to the condensate recovery. It should be noted that all the condensate recoveries reported here in three runs don't include the additional withdrawal of condensate in the slowdown process to abandonment pressure.
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