Abstract
Numerical simulations were carried out to investigate hydrodynamic forces on submarine pipelines in oscillatory flows, with a focus on the conditions under which the pipeline diameter D is of a similar order of magnitude to the boundary-layer thickness δ i.e., δ/D ∼ O(1). Two-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with shear stress transport (SST) k-ω turbulence closure were solved using a Petrov–Galerkin finite element method (PG-FEM). The effects of the seabed roughness ks/D and the Keulegan-Carpenter number KC = UmT/D on the hydrodynamic force coefficients were investigated, where ks is the Nikuradse's equivalent roughness, T is the period of oscillatory flow and Um is the amplitude of the oscillatory velocity. The diameter of the submarine pipeline is fixed at D = 0.1 m. The Reynolds number, defined as Re = UmD/υ (where ν is the kinetic fluid viscosity), ranges from 1 × 104 to 4.5 × 104. The numerical results show that the boundary-layer thickness increases with ks. Hydrodynamic force coefficients are significantly affected by δ/D in the range of δ/D ∼ O(1), while δ/D depends on ks/D and KC number. The negligence of velocity reductions in the wave boundary layer leads to overestimations of the submerged weight required for achieving on-bottom stability.
| Original language | English |
|---|---|
| Pages (from-to) | 114-123 |
| Number of pages | 10 |
| Journal | Coastal Engineering |
| Volume | 140 |
| DOIs | |
| Publication status | Published - 1 Oct 2018 |
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Effect of oscillatory boundary layer on hydrodynamic forces on pipelines. / Tang, Guoqiang; Cheng, Liang; Lu, Lin; Teng, Yunfei; Zhao, Ming; An, Hongwei.
In: Coastal Engineering, Vol. 140, 01.10.2018, p. 114-123.Research output: Contribution to journal › Article
TY - JOUR
T1 - Effect of oscillatory boundary layer on hydrodynamic forces on pipelines
AU - Tang, Guoqiang
AU - Cheng, Liang
AU - Lu, Lin
AU - Teng, Yunfei
AU - Zhao, Ming
AU - An, Hongwei
PY - 2018/10/1
Y1 - 2018/10/1
N2 - Numerical simulations were carried out to investigate hydrodynamic forces on submarine pipelines in oscillatory flows, with a focus on the conditions under which the pipeline diameter D is of a similar order of magnitude to the boundary-layer thickness δ i.e., δ/D ∼ O(1). Two-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with shear stress transport (SST) k-ω turbulence closure were solved using a Petrov–Galerkin finite element method (PG-FEM). The effects of the seabed roughness ks/D and the Keulegan-Carpenter number KC = UmT/D on the hydrodynamic force coefficients were investigated, where ks is the Nikuradse's equivalent roughness, T is the period of oscillatory flow and Um is the amplitude of the oscillatory velocity. The diameter of the submarine pipeline is fixed at D = 0.1 m. The Reynolds number, defined as Re = UmD/υ (where ν is the kinetic fluid viscosity), ranges from 1 × 104 to 4.5 × 104. The numerical results show that the boundary-layer thickness increases with ks. Hydrodynamic force coefficients are significantly affected by δ/D in the range of δ/D ∼ O(1), while δ/D depends on ks/D and KC number. The negligence of velocity reductions in the wave boundary layer leads to overestimations of the submerged weight required for achieving on-bottom stability.
AB - Numerical simulations were carried out to investigate hydrodynamic forces on submarine pipelines in oscillatory flows, with a focus on the conditions under which the pipeline diameter D is of a similar order of magnitude to the boundary-layer thickness δ i.e., δ/D ∼ O(1). Two-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with shear stress transport (SST) k-ω turbulence closure were solved using a Petrov–Galerkin finite element method (PG-FEM). The effects of the seabed roughness ks/D and the Keulegan-Carpenter number KC = UmT/D on the hydrodynamic force coefficients were investigated, where ks is the Nikuradse's equivalent roughness, T is the period of oscillatory flow and Um is the amplitude of the oscillatory velocity. The diameter of the submarine pipeline is fixed at D = 0.1 m. The Reynolds number, defined as Re = UmD/υ (where ν is the kinetic fluid viscosity), ranges from 1 × 104 to 4.5 × 104. The numerical results show that the boundary-layer thickness increases with ks. Hydrodynamic force coefficients are significantly affected by δ/D in the range of δ/D ∼ O(1), while δ/D depends on ks/D and KC number. The negligence of velocity reductions in the wave boundary layer leads to overestimations of the submerged weight required for achieving on-bottom stability.
KW - fluid force coefficients
KW - numerical simulation
KW - On-bottom stability
KW - small-diameter submarine pipeline
KW - wave boundary layer
UR - http://www.scopus.com/inward/record.url?scp=85053189109&partnerID=8YFLogxK
U2 - 10.1016/j.coastaleng.2018.06.006
DO - 10.1016/j.coastaleng.2018.06.006
M3 - Article
VL - 140
SP - 114
EP - 123
JO - Coastal Engineering
JF - Coastal Engineering
SN - 0378-3839
ER -