When you think of an external aerodynamics simulation, the first thing you need to quantify is the drag of the body under test. For example, if you want to analyze an airplane or a car, we would mainly focus on the three dominant design parameters such as lift, drag and the pitch moment. This article describes what to do on the example of the drag coefficient, but the other ones are applied with the same workflow.
This can be achieved through using SimScale, by simply setting the result outputs as described below. You find this menu under result control -> forces and moment coefficients
Lift and Drag Direction
You need to assign those according to your coordinate system. Like the following picture demonstrates, drag pulls the aircraft back. In our example, drag is in the positive x-direction. This is why we need to set the value for X-axis as 1 for the drag.
Freestream velocity is the velocity of your airplane or vehicle in most cases. You can choose the inlet velocity here.
Reference Length and Area
The reference length, in this case, is the span width of the airfoils. The reference area of an airplane is the projected frontal area, which is illustrated in the first picture.
Note that both reference length and area can change for specific cases, so we recommend finding it out for your specific application.
Pick the faces for which you want to analyze the coefficients. You can do this for single parts or the whole assembly.