The numerical study on the diffusion of turbulent submerged flows is extremely important to understand the core mechanism of the jet grouting technology, since the erosive efficiency of the jet and, consequently, the dimensions of columns strongly depends on the propagation of the jet in the space outside the nozzle. Even if the mathematical and numerical foundations of turbulence models are well known, the equations, because of closure assumptions, require dimensionless constants that can be fixed only by means of experimental data. In a previous study some of the authors presented a numerical finite-volume model simulating the turbulent diffusion of submerged jets that was initially calibrated with a set of experimental data reported in open literature, by taking into account only the variation of one model constant with the Reynolds number based on the nozzle diameter (ReD). In the present paper a multi-parameter calibration is carried out, by taking into account the variation of all the model constants with ReD. Finally, a comparison between the results obtained through single and multi-parameter calibration is performed in order to evaluate which is the best choice as a compromise between model accuracy and its simplicity.
Optimization for multi-parameter calibration in the numerical analysis of submerged flows for jet grouting
EVANGELISTA, Stefania
;GIOVINCO, Gaspare;MODONI, Giuseppe;
2015-01-01
Abstract
The numerical study on the diffusion of turbulent submerged flows is extremely important to understand the core mechanism of the jet grouting technology, since the erosive efficiency of the jet and, consequently, the dimensions of columns strongly depends on the propagation of the jet in the space outside the nozzle. Even if the mathematical and numerical foundations of turbulence models are well known, the equations, because of closure assumptions, require dimensionless constants that can be fixed only by means of experimental data. In a previous study some of the authors presented a numerical finite-volume model simulating the turbulent diffusion of submerged jets that was initially calibrated with a set of experimental data reported in open literature, by taking into account only the variation of one model constant with the Reynolds number based on the nozzle diameter (ReD). In the present paper a multi-parameter calibration is carried out, by taking into account the variation of all the model constants with ReD. Finally, a comparison between the results obtained through single and multi-parameter calibration is performed in order to evaluate which is the best choice as a compromise between model accuracy and its simplicity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
