Flow Simulation of High Flow Concrete using Incompressible Smoothed Particle Hydrodynamics (ISPH) Method

ISPH 기법을 이용한 고유동 콘크리트의 유동 해석

Abstract

A three-dimensional flow simulation model for high flow concrete was developed using Incompressible Smoothed Particle Hydrodynamics (ISPH), which can solved Navier-Stokes equation with the assumption of a fluid to be incompressible. For the simulation, a computer program code for ISPH was implemented with MATALB programming code. A piecewise cubic spline function was used for the kernel function of ISPH. Projetion method was used to calculate the velocity and pressure of particles as a function of time. Fixed ghost particle was used for wall boundary condition. Free surface boundaries were determined by using virtual density of particles. In order to validate the model and the code, the simulation results of slump flow test, $T_{500}$ test and L-box test were compared with experimental ones. The simulation results were well matched with the experimental results. The simulation described successfully the characteristics of the flow phenomenon according to the change of the viscosity and yield stress of high flow concrete.

본 연구에서는 비압축성 Navier-Stokes 방정식을 적용한 ISPH 기법을 이용하여 3차원 유동 수치해석 모델을 개발하였다. 수치해석을 위해 MATLAB을 사용하여 ISPH 프로그램을 구현하였다. ISPH의 커널 함수로 piecewise cubic spline 함수를 사용하였다. 벽 경계조건으로 고정 가상 입자를 사용하였으며, 가상 밀도를 적용하여 자유 표면 경계 부근의 입자들을 결정하였다. 수치해석 모델과 코드의 정도를 확인하기 위해 $T_{500}$ 시험, 슬럼프 플로우 시험, L-box 시험의 수치해석 결과와 실험 결과를 비교하였다. 수치해석 결과 고유동 콘크리트의 점성계수 및 항복응력 변화에 따른 유동 현상의 특성을 잘 묘사하였으며, 기존의 실험값과 비교적 잘 일치함을 확인할 수 있었다.

Figure 1. Support domain of smoothing function

Figure 2. Truncation of the kernel function near wall

Figure 3. Free surface boundary condition

Figure 4. Dimension of T₅₀₀ and slump flow test

Figure 5. Dimension of L-box test

Figure 6. Modeling by ISPH (slump cone flow test)

Figure 7. Simulated T₅₀₀

Figure 8. Simulated slump flow

Figure 9. Modeling by ISPH (L-box test)

Figure 10. Simulated L-box

Table 1. Mix proportion of high flow concrete[16]

Table 2. Summary of the result for the different test[16]

Table 3. T₅₀₀ and Slump flow prediction

Table 4. L-box prediction