Turbulence model for numerical simulation of vortex-induced vibration of rigid cylinder

Abstract

The invention provides a turbulence model for numerical simulation of vortex-induced vibration of a rigid cylinder. The model is based on a low Reynolds number k-epsilon (LSKE) turbulence model of Launder and Sharma; referring to a limiting method of a turbulence energy generation item of the SST k-omega turbulence model, turbulence energy generation items of a near-boundary region and a wake flowfield of the flow field are respectively limited, meanwhile, the turbulence energy generation items and dissipation items of different regions in the flow field are corrected through a correction function, and a turbulence model suitable for numerical simulation of vortex-induced vibration of a rigid cylinder in a subcritical Reynolds number range is established. Compared with an existing turbulence model, the turbulence model has the advantage that the calculation precision is greatly improved on the premise that the calculation speed is guaranteed in the numerical simulation of the vortex-induced vibration of the rigid cylinder.

Description

technical field [0001] The invention relates to a numerical model of vortex-induced vibration of an ocean pipeline, in particular to a turbulence model for numerical simulation of rigid cylinder vortex-induced vibration. Background technique [0002] In the process of offshore oil and gas development, the offshore pipeline is an important part connecting the offshore operating platform and the subsea wellhead. Usually, the in-service period of the offshore pipeline is very long, and the fatigue design is an important part of the pipeline design. The API specification and the Norwegian DNV specification are identified as the main factors causing fatigue damage. Due to the extremely complex vibration of marine pipelines, in order to better understand the essence of pipeline vortex-induced vibration problems, numerical research is often simplified to a rigid cylinder model to study its vibration response characteristics. The prediction of vibration response plays a guiding and...

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Problems solved by technology

At present, the SST k-ω turbulence model and the low Reynolds number k-ε (LSKE) turbulence model of Launder and Sharma are widely used and the simulation results are relatively good, but they still cannot accurately simulate rigid cylinders in the subcritical Reynolds number range. The characteristics of body vortex-induced vibration, and the applicable Reynolds number range is also extremely limited, in which the boundary layer separation angle, St number, lift and drag coefficients, hysteresis interval, maximum amplitude, and the range of different response branches all have different degrees of deviation. It is due to the over-prediction of the turbulent viscosity coefficient in the near-boundary area and the wake field that the transition of the boundary layer occurs prematurely, which causes the separation point to move backward and the parameters such as lift and drag coefficients to deviate, thus affecting the vortex-induced vibration of the rigid cylinder. have a serious impact on the simulation results of

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