In this paper, two-dimensional turbulent flows in different and complex geometries are simulated by using an accurate grid generation method. In order to analyze the fluid flow, numerical solution of the continuity and Navier-Stokes equations are solved using CFD techniques. Considering the complexity of the physical geometry, conformal mapping is used to generate an orthogonal grid by means of...

in this study, a numerical computational fluid dynamics study is conducted in order to predict the aerodynamic forces on the np car. the turbulent air flow around the car is modeled using the realizable k-ε model. first, results are validated against those presented for the ahmed’s body. next, the fluid flow around the car is simulated for different car speeds ( to mph) and flow directions ( to...

in this paper wave transformation in a submerged sloped breakwater and its hydraulic performance was simulated by developing a numerical model in fortran. the code was established by combining porous flow and a two-phase model using vof method. modified navier-stokes and k-ε equations implemented to the model to simulate the flow in porous media. cut cell method was modified to simulate fluid t...

UNLABELLED Accurate prediction of ventilation flow is of primary importance for designing a healthy, comfortable, and energy-efficient indoor environment. Since the 1970s, the use of computational fluid dynamics (CFD) has increased tremendously, and nowadays, it is one of the primary methods to assess ventilation flow in buildings. The most commonly used numerical approach consists of solving t...

We analyze the rare kaon decays KL → π0νν̄, K+ → π+νν̄, KL → π0e+e− and KL → μ+μ− in conjunction with the CP violating ratio ε/ε in a general class of supersymmetric models in which Zand magnetic-penguin contributions can be substantially larger than in the Standard Model. We point out that radiative effects relate the double left-right mass insertion to the single left-left one, and that the phe...

A natural generalization of graph Ramsey theory is the study of unavoidable subgraphs in large colored graphs. In this paper, we find a minimal family of unavoidable graphs in two-edgecolored graphs. Namely, for a positive even integer k, let Sk be the family of two-edge-colored graphs on k vertices such that one of the colors forms either two disjoint Kk/2s or simply one Kk/2. Bollobás conject...

We give algorithms for approximation by low-rank positive semidefinite (PSD) matrices. For symmetric input matrix A ∈ Rn×n, target rank k, and error parameter ε > 0, one algorithm finds with constant probability a PSD matrix Ỹ of rank k such that ‖A− Ỹ ‖2F ≤ (1+ε)‖A−Ak,+‖ 2 F , where Ak,+ denotes the best rank-k PSD approximation to A, and the norm is Frobenius. The algorithm takes time O(nnz(A...

and Applied Analysis 3 = [− 0.5k 1 x 1.5 1 + 0.5k 1 x 1 + 0.5 (r 1 − ε 12 − 0.25σ 2 1 ) x 0.5 1 − 0.5 (r 1 − ε 12 − 0.5σ 2 1 )] dt + [− 0.5k 2 x 1.5 2 + 0.5k 2 x 2 + 0.5 (r 2 − ε 21 − 0.25σ 2 2 ) x 0.5 2 − 0.5 (r 2 − ε 21 − 0.5σ 2 2 )] dt + [0.5 (x −0.5 1 − x −1 1 ) ε 12 x 2 + 0.5 (x −0.5 2 − x −1 2 ) ε 21 x 1 ] dt + 0.5 (x 0.5 1 − 1) σ 1 dB 1 (t) + 0.5 (x 0.5 2 − 1) σ 2 dB 2 (t) . (11) There e...

In this paper we study the model of ε-smoothed k-CNF formulas. Starting from an arbitrary instance F with n variables and m = dn clauses, apply the ε-smoothing operation of flipping the polarity of every literal in every clause independently at random with probability ε. Keeping ε and k fixed, and letting the density d = m/n grow, it is rather easy to see that for d ≥ ε−k ln 2, F becomes whp un...