A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Numerical modeling of pipe leakage in variably saturated soil
Pipe leakage related to defect urban sewer and stormwater pipe networks may lead to subsurface contamination, reduction of groundwater recharge or a significant decrease of the groundwater table. The quantification of pipe leakage is challenging, mostly due to the uncertain forming of a colmation layer in the defect vicinity and inaccessibility of both, pipe defects and the surrounding soil. Numerical models can be used to quantify leakage. At present times, only few physically-based pipe leakage models exist, all of which either neglect or simplify variably-saturated flow. In the present dissertation, a novel and unique three-dimensional physically-based pipe leakage model for variably saturated soil is presented. The model consists of the newly implemented coupling between the pipe flow simulator HYSTEM-EXTRAN and the unsaturated-saturated flow simulator OpenGeoSys. The coupling is based on updating of boundary conditions and source terms. The interprocess data transfer is realized using a shared-memory. The pipe leakage model is successfully validated and verified using a newly generated benchmark library for pipe leakage models. Benchmarks are based on two physical experiments described in literature and two newly derived analytical solutions. A novel method for upscaling pipe leakage is presented. The method enables to significantly reduce the local refinement of spatial discretization in the pipe vicinity, which leads to a substantial reduction of computational costs. The method is based on leakage functions. Two leakage functions representing both, sewer and stormwater pipe leakage are presented. Accuracy and time efficiency of the upscaling method is demonstrated by comparing results from a fully discretized model and an upscaled model. In the present dissertation, the pipe leakage model is applied to several case studies to investigate the pipe leakage process. Model setups represent (i) a single defect, (ii) a leaky sewer pipe of 30 m length, and (iii) a 53 km long defect stormwater pipe network in an ...
Numerical modeling of pipe leakage in variably saturated soil
Pipe leakage related to defect urban sewer and stormwater pipe networks may lead to subsurface contamination, reduction of groundwater recharge or a significant decrease of the groundwater table. The quantification of pipe leakage is challenging, mostly due to the uncertain forming of a colmation layer in the defect vicinity and inaccessibility of both, pipe defects and the surrounding soil. Numerical models can be used to quantify leakage. At present times, only few physically-based pipe leakage models exist, all of which either neglect or simplify variably-saturated flow. In the present dissertation, a novel and unique three-dimensional physically-based pipe leakage model for variably saturated soil is presented. The model consists of the newly implemented coupling between the pipe flow simulator HYSTEM-EXTRAN and the unsaturated-saturated flow simulator OpenGeoSys. The coupling is based on updating of boundary conditions and source terms. The interprocess data transfer is realized using a shared-memory. The pipe leakage model is successfully validated and verified using a newly generated benchmark library for pipe leakage models. Benchmarks are based on two physical experiments described in literature and two newly derived analytical solutions. A novel method for upscaling pipe leakage is presented. The method enables to significantly reduce the local refinement of spatial discretization in the pipe vicinity, which leads to a substantial reduction of computational costs. The method is based on leakage functions. Two leakage functions representing both, sewer and stormwater pipe leakage are presented. Accuracy and time efficiency of the upscaling method is demonstrated by comparing results from a fully discretized model and an upscaled model. In the present dissertation, the pipe leakage model is applied to several case studies to investigate the pipe leakage process. Model setups represent (i) a single defect, (ii) a leaky sewer pipe of 30 m length, and (iii) a 53 km long defect stormwater pipe network in an ...
Numerical modeling of pipe leakage in variably saturated soil
Peche, Aaron (author) / Graf, Thomas
2019-01-01
Bericht / Institut für Strömungsmechanik und Umweltphysik im Bauwesen der Leibniz Universität Hannover;86
Book
Electronic Resource
English
Numerical modeling of pipe leakage in variably saturated soil
| TIBKAT | 2019
Numerical modeling of pipe leakage in variably saturated soil
| TIBKAT | 2018
Numerical modeling of pipe leakage in variably saturated soil
| UB Braunschweig | 2019
Modeling Flow in Variably-Saturated Porous Media
| British Library Conference Proceedings | 1994