Wall-resolved Large Eddy Simulation of a flow through a square-edged orifice in a round pipe at Re = 25,000

Abstract

The orifice plate is a pressure differential device frequently used for flow measurements in pipes across different industries. The present study demonstrates the accuracy obtainable using a wallresolved Large Eddy Simulation (LES) approach to predict the velocity, the Reynolds stresses, the pressure loss and the discharge coefficient for a flow through a square-edged orifice in a round pipe at a Reynolds number of 25000. The ratio of the orifice diameter to the pipe diameter is = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11. The mesh is sized using refinement criteria at the wall and preliminary RANS results to ensure that the solution is resolved beyond an estimated Taylor micro-scale. The inlet condition is simulated using a recycling method, and the LES is run with a dynamic Smagorinsky sub-grid scale (SGS) model. The sensitivity to the SGS model and to the pressure-velocity coupling is shown to be small in the present study. The LES is compared with the available experimental data and ISO 5167-2. In general, the LES shows good agreement with the velocity from the experimental data. The profiles of the Reynolds stresses are similar, but an offset is observed in the diagonal stresses. The pressure loss and discharge coefficients are shown to be in very good agreement with the predictions of ISO 5167-2. Therefore, the wall-resolved LES is shown to be highly accurate in simulating the flow across a square-edged orifice.

Dynamic localized turbulent diffusion and its impact on the galactic ecosystem

“…The dynamic Smagorinsky model has, to our knowledge, not yet been implemented and investigated in cosmological simulations. The model has, however, been validated extensively in the fluid simulation community by comparing to the results of standard numerical tests and experiment data, and has been shown to improve upon the constantcoefficient model (Kleissl et al 2006;Kirkpatrick et al 2006;Benhamadouche et al 2017;Lee & Cant 2017;Kara & Çaglar 2018;Taghinia et al 2018). In the dynamic model, the sub-grid properties of a turbulent fluid are computed under two assumptions 3 : (i) the behaviour of the largest unresolved eddies is entirely determined by their interactions with the eddies on the smallest resolved scales, and (ii) these interactions are analogous to those between the fluid motions on the smallest resolved scale and the motions on larger scales.…”

On the use of (U)RANS and LES approaches for turbulent incompressible single phase flows in nuclear engineering applications

“…In the present case. Only the wall-modeled approach is able to predict a discharge coefficient not very sensitive to the mesh refinement and within less that 1% of the ISO correlation value (a wall-resolved LES in Benhamadouche et al (2015a) gives a discharge coefficient very close to the one given by the ISO).…”

“…3. Several computations (not all shown here but the reader can refer to Benhamadouche et al, 2015aBenhamadouche et al, , 2015b have been performed for the flow through a square edged orifice plate at a Reynolds number equal to 25000, based on the bulk velocity Ub in the main pipe and the diameter of this latter. The ratio of the orifice diameter to the pipe diameter is = 0.62, and the ratio of the orifice thickness to the pipe diameter is 0.11.…”

Large Eddy Simulation for flows through emerged or slightly submerged square obstacles

“…The meshes are of hexahedric shape. The LES capabilities of Code_Saturne have been on various academic and industrial cases including decaying isotropic turbulence, channel flows, side-byside cylinders, tube bundles and gusts over a plate; (see Benhamadouche 2006, Benhamadouche et al 2017, 2019 for example. The temporal discretization for the LES is second order Crank-Nicolson in time with linearized convection.…”