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This test simulates the flow of concrete into rectangular formwork. The concrete is initially kept in a rectangular reservoir and released by lifting the vertical gate due to gravity forces. This simulation has been performed in 3D to illustrate the capability of simulation code to solve 3D problems. The geometry of the tests is shown in Fig. 1. The dimensions of the rectangular formwork are 0.7 x 0.2 x 0.15 [m], and the dimensions of the box with concrete are 0.27 x 0.2 x 0.12 [m]. Concrete flows only due to gravity. The main focus is to assess the influence of boundary conditions and the effect of varying yield stress.

Fig.1: The geometry of the LCPC test	Fig.2: Computational mesh

The computational model consists of a total of 10052 nodes and 50880 tetrahedral elements with a linear approximation of velocity and pressure fields. In total, 20 time steps were used in the simulation. Concrete is modeled as a Bingham fluid with different material parameters. On all vertical walls and the bottom of the box, “slip with friction” boundary conditions are prescribed (the normal velocity component is set to zero, and the tangential component is proportional to the stress vector). The top of the box is assumed to be opened, and a zero-pressure boundary is assumed.

An example of OOFEM input for LCPC Box simulation can be downloaded from here: channel_beta20_tau40_mu40_oofem.in

The videos below compare the flow with different friction and yield stress values. In the first video, concrete has yield stress equal to 40 [Pa] and plastic viscosity 40 [Pa.s], while the friction parameters are 10.0 and 80.0. In the second video, the friction parameter is in both cases equal to 20.0 and plastic viscosity to 40 [Pa.s], while yield stress is 40 [Pa] and 400 [Pa].

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