IntroductionThe turbulent flow is more chaotic and random motion than the laminar flow. It is difficult to expect the turbulent flow which has chaotic and random motion. Nevertheless, we use the Navier-Stokes equation derived by using statistical quantities to expect the turbulent flow. The velocity component can be expressed like equation (1) by using Reynolds decomposition.<중 략>Case1-(a) Flat Plate -SA modelThe GeometryThis report uses the blockMesh which is fundamental utility in OpenFOAM to make the geometry and the mesh for simulation. The computational domain is created like NASA CFL3D mesh. The wall where x is -0.3m to 0m is symmetry plane because this domain is free-stream which has no normal velocity component. The upper wall where x is 0m to 2m is slip wall and the bottom wall is no slip wall.Figure 1 the geometry of flat plateThe number of x axis grid is 545 and the number of y axis grid is 385. To capture the very thin turbulent boundary layer and entrance region, the y axis grid and the x axis grid is generated by non-uniform.
1. Laminar incompressible boundary layer flow (2D)A. Theoretical approachThe boundary layer is thin layer in the flow. This phenomenon is caused by viscosity.Outside of the boundary layer, the flow is inviscid flow. In viscous region, we can not use the Euler equation which is used for inviscid flow. So, we need the other equation for viscous flow. That is the boundary layer equation. We can express the Navier-Stokes equation for the boundary layer.<중 략>C. Comparison between theoretical and computational approachesFor comparison, the variables make same variable which is eta and velocity is normalized. Comparing the calculated results with the theoretical results is as follows.Figure 11. The comparison computational normalized x velocity with theoretical results(x=1.0m)The blue line is the theoretical results by using matlab code of the normalized x-velocity.The red line is the calculated results by using fluent program of normalized x-velocity.
Key Words: Y_Plus, Reynolds number, Laminar flow, Turbulent flowAbstract: I determine if there is a laminar flow or turbulent flow after calculating thenumber of Reynolds each through the Y_plus calculator. I create a mesh suitable forinterpreting each flow. Set the settings for each situation and interpret the flow field. Idetermine the convergence by looking at the residual and analyze the flow through PostCFD.1. IntroductionI determine if there is a laminar flow or turbulent flow after calculating the number ofReynolds each through the Y_plus calculator. If the number of Reynolds is less than 2300in an internal flow, the flow is laminar flow. If the number of Reynolds is higher than2300 in an internal flow, the flow is turbulent flow. I create a mesh suitable forinterpreting each flow. If the flow is turbulent flow, Inflation (Making mesh) will be usedto account for turbulent flow. Set the settings for each situation and interpret the flowfield.
1. 서론종이 자이로콥터를 설계 변수에 따라서 체공시간 을 구하는 실험을 하여서 그 결과들 중 임의적으 로 9가지를 골라 Sample point를 만든다. 그런 후 에 Factor levels 와 orthogonal array를 고른다. 응 답표면을 만들고 Matlab function, fminuncon을 이 용하여 최적화를 시키고 최적 값을 도출한다. Discrete approach를 이용하여 설계 변수를 최적화 를 시키고 최적 값을 도출한다. 그런 뒤 두 가지 의 방법을 이용하여 도출한 최적 값을 비교하고, 서로의 차이점에 대해서 분석할 것입니다.2. 본 론종이 자이로콥터를 정해진 설계 조건에 맞게 여러 가지 종류를 만들었습니다. 외풍에 의해 결과의 에러 값이 커지지 않도록 최대한 바람에 불지 않는 새날관에서 실험을 진행하였습니다. 사람들이 최대한 다니지 않을 때, 실험을 하며 공기 흐름의 영향도 최소화하여서 실험을 진행하였습니 다.