Kiril S. Shterev

Bulgarian Academy of Sciences | BAS · Institute of Mechanics

The fluid–structure interaction is one of the most important coupled problems in mechanics. The topic is crucial for many high-technology areas. This work considers the interaction between an elastic obstacle and rarefied gas flow, seeking specific problems that arise during this interaction. The Direct Simulation Monte Carlo method was used to mod...

Micro-electromechanical systems (MEMS) have developed rapidly in recent years in various technical fields that have increased their interest in the Direct Simulation Monte Carlo (DSMC) method. In this paper, we present a simple representation of the DSMC collision scheme and investigate the correctness of the Simplified Bernoulli Trial (SBT) collis...

The work is devoted to study 2D pressure driven rarefied gas flow in a microchannel having an elastic obstacle. The elastic obstacle is clamped at the bottom channel wall and its length is half of the channel height. The gas flow is simulated by Direct Simulation Monte Carlo (DSMC) method applying the advanced Simplified Bernoulli Trial (SBT) colli...

Numerical approach and computer code are developed to study 2D rarefied gas flow in a microchannel having an elastic obstacle. A Couette rarefied gas flow passing an elastic beam clamped to the fixed bottom wall is considered as a test case. The gas flow is simulated by the direct simulation Monte Carlo (DSMC) method applying the advanced Simplifie...

The recent trend of using Graphics Processing Units (GPU's) for high performance computations is driven by the high ratio of price performance for these units, complemented by their cost effectiveness. At first glance, computational fluid dynamics (CFD) solvers match perfectly to GPU resources because these solvers make intensive calculations and u...

Recent decades are put a lots of efforts to develop higher-order scheme for convective term approximation that is stable and reliable. On the other hand, diffusion terms are easily approximated with numerical schemes with at least second accuracy. The reason is that numerical schemes for diffusion term approximation as central difference correspond...

In this paper, the transition between steady and unsteady regimes of the two-dimensional gas flow past a moving square cylinder confined between two parallel plates with equal temperatures was investigated for different subsonic and transonic speeds and blockage ratios B=3, 5, 10 and 20 (B is the ratio between microchannel height and square size)....

The rapidly emerging industry of micro-electro-mechanical devices gives rise to new potential microfluidic applications. The analysis of the possible flow regimes is an important task of any microfluidic investigation. For a gas flow the transition between steady and unsteady regimes occurs at small Knudsen number Kn < 0.1 (Kn = 0 /L, where 0 is th...

The influence of transversal walls on a stationary near-isothermal gas flow in three dimensional microchannel configurations is studied using the Direct Simulation Monte Carlo (DSMC) method in the late slip regime and the transitional regime of the gas flow, for some selected values of the rarefaction parameter. The study was performed considering...

In this paper, extrapolation technique is introduced in the Semi-Implicit Method for Pressure-Linked Equations - Time Step (SIMPLE-TS) finite volume iterative algorithm for calculation of compressible Navier–Stokes–Fourier equations subject of slip and jump boundary conditions. The initial state, required by the iterative solver in simulation of un...

The rapidly emerging industry of micro-electro-mechanical devices gives rise to new potential microfluidic applications. The analysis of the possible flow regimes is an important task of any microfluidic investigation. For unstable rarefied gas flows the transition between steady and unsteady regimes occurs at small Knudsen number Kn < 0.1 (Kn =...

The recent trend of using Graphics Processing Units (GPUs) for high performance computations is driven by the high ratio of price performance for these units, complemented by their cost effectiveness. Such kinds of units are increasingly being deployed not only as accelerators for supercomputer installations, but also in GPU-enabled nodes in Grid a...

The rapidly emerging industry of micro-electro-mechanical devices gives rise to new potential microfluidic applications. The analysis of the possible flow regimes is an important task of any microfluidic investigation. For a gas flow the transition between steady and unsteady regimes occurs at small Knudsen number Kn < 0.1 (Kn = ℓ0 / L, where ℓ0 is...

The present work is related to the study of the pressure driven isothermal gas flows through different microchannel configurations such as short straight micro-channels, 90 degrees bend channels and T-shaped junctions. The direct simulation Monte Carlo (DSMC) method is used to calculate the gas flow through channel configurations in order to distin...

Rapidly emerging micro-electro-mechanical devices create new potential microfluidic applications. A simulation of an internal and external gas flows is important for their design. For small Knudsen number Kn < 0.1 (Kn = l 0/L, where l 0 is the mean free path of the gas molecules and L is the characteristic length), a continuum approach based on mo...

Rapidly emerging micro-electro-mechanical devices create new potential microfluidic applications. A simulation of an internal and external gas flows with accurate boundary conditions for these devices is important for their design. In this paper we study influence of reservoirs used at the microchannel inlet and outlet on the characteristics of the...

In this paper a parallel version of the finite volume method SIMPLE-TS for calculation of two-dimensional compressible, viscous gas flows with improved performance is presented. It is demonstrated on a problem regarded to micro gas flows, taking place in Micro-Electro-Mechanical Systems (MEMS). The reorganisation of the parallel algo-rithm improve...

Micro mechanical devices are rapidly emerging technology, where new potential applications are continuously being found. A simulation of internal and external gas flows in or around these devices is important for their design. The gas flows are characterized with areas of low speed flows (low Reynolds numbers). The flows can go from high speed supe...

It is developed iterative algorithm SIMPLE-TS (Time Step) for calculation of unsteady, viscous, compressible, heat-conductive gas flows. The main idea implemented in the algorithm is maximal satisfaction of the equation of state during entire iterative process. No under-relaxation coefficients are used to ensure convergence of the algorithm. The de...

A pressure based, iterative finite volume method is developed for calculation of compressible, viscous, heat conductive gas flows at all speeds. The method does not need the use of under-relaxation coefficient in order to ensure a convergence of the iterative process. The method is derived from a general form of system of equations describing the m...

In this paper a parallel organization of a finite volume algorithm for calculation of two-dimensional compressible, viscous gas flows is presented The problem is addressed to the new emerging area of the micro gas flows, taking place in Micro-Electro-Mechanical Systems (MEMS) Technically, the parallel algorithm is organized by using standard MPI, n...

In this paper we study the movement with constant velocity of a square-shaped particle confined in a microchannel filled with hard-sphere monoatomic gas. The problem is solved using two completely different methods: direct simulation Monte Carlo (DSMC) (molecular approach) and finite volume method (FVM) (continuum approach). Continuum model is desc...