March 10, 2020
The drag coefficient is a number that aerodynamicists use to model all of the complex dependencies of shape, inclination, and flow conditions on aircraft drag. This equation is simply a rearrangement of the drag equation where we solve for the drag coefficient in terms of the other variables. The drag coefficient Cd is equal to the drag D divided by the quantity: density r times half the velocity V squared times the reference area A.
Cd = D / (A * .5 * r * V^2)
The quantity one half the density times the velocity squared is called the dynamic pressure q. So
Cd = D / (q * A)
The drag coefficient then expresses the ratio of the drag force to the force produced by the dynamic pressure times the area.
This equation gives us a way to determine a value for the drag coefficient. In a controlled environment (wind tunnel) we can set the velocity, density, and area and measure the drag produced. Through division we arrive at a value for the drag coefficient. As pointed out on the drag equation slide, the choice of reference area (wing area, frontal area, surface area, …) will affect the actual numerical value of the drag coefficient that is calculated. When reporting drag coefficient values, it is important to specify the reference area that is used to determine the coefficient. We can predict the drag that will be produced under a different set of velocity, density (altitude), and area conditions using the drag equation.
In this tutorial, you will learn how to use the Reference Values window for a 2D simulation- With Reference Values (Lenght, Depth, Area, etc.), you can find the Drag Coefficient. In this case, the experimental Drag coefficient (Cd) is 1.55.
Ansys Fluent Tutorial | Heatsink
In this tutorial, you will learn how to simulate a Heatsink using Ansys Fluent. In this first video, you will see how to create the geometry and the mesh using DesignModeler, Ansys Meshing and Ansys Fluent.
Ansys Fluent | Hydraulic Jump
Free surface is the surface of a fluid that is subject to...
Ansys Fluent | Hydraulic Jump
Free surface is the surface of a fluid that is subject to zero parallel shear stress, such as the interface between two homogeneous fluids, for example, liquid water and the air in the Earth's atmosphere. Unlike liquids, gases cannot form a free surface on their...
Ansys Fluent | Blower | Mesh Motion (Unsteady)
In this tutorial, you will learn how to simulate a blower (unsteady) using Mesh Motion with Ansys Fluent. Please download the mesh.
Ansys Fluent Tutorial – Blower
In this tutorial you will learn how to simulate a Blowe using Ansys Fluent through multiple reference frame.
OpenFOAM Tutorial | Multiphase Simulation
In this tutorial you will learn how to simulate a multiphase simulation through lockExchange tutorial that comes by default with OpenFOAM.
OpenFOAM Tutorial | motorBike (simpleFoam)
In this video you will learn how to simulate motorBike tutorial using OpenFOAM with simpleFoam solver.
OpenFOAM Tutorial | How to create an Animation
In this tutorial you will learn how to create an animation using OpenFOAM through Paraview (paraFoam Command).
Stay Up to Date With The Latest News & Updates
Help us keep growing
CFD.NINJA is financed with its own resources, if you want to support us we will be grateful.
Join Our Newsletter
Subscribe to receive emails with detailed information related to the CFD.
Subscribe to our social networks to receive notifications about our new tutorials