Multiscale Simulation of Cardiovascular flows on the IBM Bluegene/P: Full Heart-Circulation System at Red-Blood Cell Resolution

Abstract

We present the first large-scale simulation of blood flow in the coronary artieries and other vessels supplying blood to the heart muscle, with a realistic description of human arterial geometry at spatial resolutions from centimeters down to 10 microns (near the size of red blood cells). This multiscale simulation resolves the fluid into a billion volume units, embedded in a bounding space of 300 billion voxels, coupled with the concurrent motion of 300 million red blood cells, which interact with one another and with the surrounding fluid. The level of detail is sufficient to describe phenomena of potential physiological and clinical significance, such as the development of atherosclerotic plaques. The simulation achieves excellent scalability on up to 294, 912 Blue Gene/P computational cores.

Performance Analysis of the Lattice Boltzmann Model Beyond Navier-Stokes

“…In order to maximize messaging performance and set the code up for an easy transition to the use of indirect addressing necessary for irregular domains, the distribution functions were stored in two dimensional arrays of (N umV elocities, zDim · yDim · xDim) allocated in contiguous memory. [1]. Fig.…”

“…f (x+c i ∆t, t+∆t) = f (x, t)−ω∆t(f (x, t)−f eq (x, t)) (1) There are two key components to the algorithm: collision and advection. The collision step is calculated through a relaxation towards local equilibrium, as shown in the right hand side of Eq.…”

“…The collision step is calculated through a relaxation towards local equilibrium, as shown in the right hand side of Eq. (1). In this work, we use the most common collision operator, the Bhatnagar-Gross-Krook (BGK), which relaxes to equilibrium on a single time scale [13].…”

“…In this work, we focus on two velocity models. For continuum flow, we use the common 19-speed cubic D3Q19 lattice connecting each lattice point to its first and second neighbors [1]. The associated weights and discretized velocities are given in Table I.…”

“…We have developed a multiscale fluid dynamics simulation that models flow in complicated geometries from microfluidic devices to patient-specific arterial geometries obtained from computed tomography (CT) scans [1], [2]. Our initial models have focused on flow in the coronary arteries where the diameters are on the order of millimeters as shown in Fig.…”