Direct numerical simulations (DNS) of flow over an NACA-0012 airfoil are performed at a low and a moderate Reynolds numbers of Rec=50*10 and 1*10. The angles of attack are 5 and 15 degrees at the low and the moderate Reynolds number cases respectively. The three-dimensional unsteady compressible Navier-Stokes equations are solved using higher order compact schemes. The flow field in the low Rey...

Ducted propeller is a method on the modification which added duct/nozzle propeller. application aimed to increase thrust, efficiency, and decrease noise vibration. In this research, numerical simulation was conducted using ANSYS Fluent 2020 R2 with k-epsilon solver model. The aim of research analyze effect duct geometry Ld/D (duct length/duct diameter) ratio. done two variations at three differ...

Multiple numerical solutions of inviscid transonic flow over several airfoils exist at certain Mach number and angle of attack. Global linear stability analysis of the multiple solutions is conducted in this paper. Linear perturbation equations of the Euler equations around a steady-state solution are formed, an eigenvalue problem is then constructed using the modal analysis approach, then it i...

A six-coloring of the Euclidean plane is constructed such that the distance 1 is not realized by any color except one, which does not realize the distance x/2 1. A 44-year-old problem due to Edward Nelson asks to find the chromatic number x(E 2) of the plane, i.e. the minimal number of colors that are required for coloring the plane so that no two points, a unit distance apart, lie on the same ...