Zakharov Y.N.   Nudner I.S.   Geidarov N.A.   Ivanov K.   Semenov K.K.   Stukolov S.   Yushkov A.  

Computational Investigation of Turbulent Flow Impact on Noncohesive Soil Erosion near Foundations of Gravity Type Oil Platforms

Reporter: Ivanov K.

    Gravity type oil platforms at shallow marine coastal areas are currently used for oil extraction. Processes of bottom soil erosion near foundations of those platforms and analyses of their stability problems are of great interest. Laboratory-based experiments, seminatural physics experiments and mathematical model approaches have been recently used to study those problems. Papers [1-3] show the results of many experimental investigations and computational investigations of noncohesive soil erosion near foundation of the platform “Prirazlomnaya”, comparative tables of laboratory experiments and computational experiments, analysis of different wave modes of fluid flow impact on bottom material particle transportation. Fluid flow mode is supposed to be laminar. The paper studies flow developed turbulence impact on erosions and soil load development near foundations of gravity type oil platform by using experimental and computational investigations.
    To calculate turbulent fluid flow LES method is used due to the significant flow unsteadiness. Both algebraic and differential models are used to model subgrid viscosity. Morphological model [6] based on balance of forces which effect soil particles is used together with the model described in [4,5] to calculate soil erosion.
    The results of experimental and computational investigations of soil erosion in the context of flow developed turbulence with variable input parameters are shown. Qualitative erosion patterns and its quantitative characteristics are compared to laminar fluid flow modes.

References

[1] Gaydarov N.A. Computational and experimental investigations of soil erosion near foundations of gravitational type platforms due to currents [Text]/ N.A.Gaydarov, Y.N.Zakharov, K.S. Ivanov, V.V. Lebedev.  A.V.Mishina,  I.S.Nudner, K.K.Semenov, L.G.Schemelinin // Applied technologies of hydroacoustics and hydrophysics (GA 2014): XII all-Russia conference papers, Saint-Petersburg, May 27-29, 2014, St.Petersburg: Nestor-Istorya, 2014. 626 p.- pp.239-241

[2] Gaydarov N.A., Zakharov Y.N., Ivanov K.S., Semenov K.K., Lebedev V.V., Nudner I.S., Belyaev N.D., Mishina A.V., Schemelinin L.G. Numerical and Experimental Studies of Soil Scour Caused by Currents near Foundations of Gravity-Type Platforms. Proceedings of 2014 International Conference on Civil Engineering, Energy and Environment (CEEE-2014), Hong Kong, 13-14 December 2014, pp. 190-197.
[3] Semenov K.K.,  Lebedev V.V.,  Nudner I.S.,  Geidarov N.A.,  Ivanov K.S., Zakharov Y.N.,  Belyaev N.D.,  Mishina A.V.,  Schemelinin L.G.  Impact  of waves and currents on the soil near gravity-type offshore platform foundation: numerical and experimental studies // Proceedings of ISOPE-2015, Kona, Hawaii, paper 2015-TPC-0375
[4] Brørs B. Numerical modeling of flow and scour at pipelines // J. Hydraul. Eng. 1999. V. 125. pp. 511-523.
[5] Solberg T., Hjertager B. H., Bove S. CFD modelling of scour around offshore wind turbines in areas with strong currents // Tech. Rep. 5. Esbjerg Institute of Technologym Aalborg University. 2005.
[6] Roulund A., Sumer B. M, Fredsøe J., Michelsen J. Numerical and  experimental  investigation  of  flow  and  scour  around  a  circular pile // J. Fluid Mech. 2005. V. 534. pp. 351-401.