# CFD & Design at GATEpathshala

Posted by: admin,   23-Jun-2016, 5:11 am

# CFD & Design Program:

This course, taught in GATEpathshala by several IITians, serves as an introduction to computational techniques arising in aerospace engineering. Applications are drawn from aerospace topics, aerodynamics, fluid dynamics, rocket propulsion and orbital mechanics.

Techniques include: numerical integration of systems of ordinary differential equations; finite-difference, finite-volume, and particle methods discretization of partial differential equations; numerical linear algebra; eigenvalue problems; and grid generation techniques: Delaunay triangulation, Polygon mesh, Unstructured grid, Structured grid, etc.

Institution: Gate Pathshala Educational Services LLP.

## Boundary Layer GUI: MATLAB App provides a GUI to study laminar boundary layer problem of flow over a flat plate. This is the 1st MATLAB App in the Virtual Thermal/Fluid Lab series. This MATLAB App allows you to:

• Visualize a boundary layer
• Study the growth of boundary layer thickness in response to free-stream velocity
• Visualize streamlines and velocity profile
• Learn how to solve boundary layer problem numerically with TDMA
• Look at the GUI source code and see how it is created

## 3D Lifting Surfaces through Vortex Lattice Methods(VLM) There is a method that is similar to panel methods but very easy to use and capable of providing remarkable insight into wing aerodynamics and component interaction. It is the vortex lattice method (vlm), and was among the earliest methods utilizing computers to actually assist aerodynamicists in estimating aircraft aerodynamics. Vortex lattice methods are based on solutions to Laplace’s Equation, and are subject to the same basic theoretical restrictions that apply to panel methods.

As a comparison, vortex lattice methods are:

Similar to Panel methods:

• singularities are placed on a surface
• the non-penetration condition is satisfied at a number of control points
• a system of linear algebraic equations is solved to determine singularity strengths

Different from Panel methods:

• Oriented toward lifting effects, and classical formulations ignore thickness
• Boundary conditions (BCs) are applied on a mean surface, not the actual surface (not an exact solution of Laplace’s equation over a body, but embodies some additional approximations, i.e., together with the first item, we find dCp,not Cp upper and Cp lower)
• Singularities are not distributed over the entire surface
• Oriented toward combinations of thin lifting surfaces (recall Panel methods had no limitations on thickness).

Vortex lattice methods were first formulated in the late 30’s, and the method was first called “Vortex Lattice” in 1943 by Faulkner. The concept is extremely simple, but because of its purely numerical approach (i.e., no answers are available at all without finding the numerical solution of a matrix too large for routine hand calculation) practical applications awaited sufficient development of computers—the early 60’s saw widespread adoption of the method.