What do your results mean?

This guide explains the POSTPRO generated by the TS Truck App. T If you still have questions regarding your results, please email us at app-support@totalsim.us

Plots and Movie Slices


This chart will list variables that could be generated by your App. Solutions usually include but are not limited to the following

The coefficients are normalized by freestream dynamic pressure. Dynamic pressure is equal to the one half of the fluid density and freestream velocity.

Cf and tauwMean also include LIC images and slices. LIC is surface streamlines overlaid on the surface to indicate the vector orientation of the local shear-stress.

The plots show the surface shear stress of the vehicle. Low levels of shear stress indicates that the flow could be separated at that region or has thick boundary layer at that region. Separated areas tend to accumulate drag.

The baseline truck geometry was ran without skirt and boat tail as well as with both the skirt and boat tail. The view above is the rear of the trailer. We can see that these regions went from green in the run without boat tail and skirt to grey in the run with boat tail and skirt. This shows that the boat tail and skirt features helped reduced low pressure on the rear of the trailer as well as the rear wheels. Low pressure on rear-facing surfaces (e.g. back face of the trailer) tend to suck the vehicle backwards which integrates into drag.

From the CpY above, we can see a positive CpY on the right side of the vehicle and a negative CpY on the left side. In this case the vehicle is oriented such that the Y axis points out the right side of the vehicle. Hence as the flow accelerates off the front windscreen and around the A-pillar, the low pressure wants to suck the right-hand-side of the car out to the right (+Y direction) and the left-hand-side to the left (-Y direction). For symmetric steady state runs, the magnitudes are similar and thus summing the right and left sides of the car tends to equate to a near zero value

XRay Plots

These plots show the summation of the Downforce/Lift or Drag in their project views as if CpX (Drag) or CpZ (Downforce/Lift) values were squished onto a single plane. This will give you a good sense as to which areas on the vehicle the pressure differential between the top/bottom or front/back are more beneficial or detrimental to downforce/lift or drag.

Downforce XRay
Drag XRay

Drag and Downforce Accumulation

The Accumulation plots show which x-location (front tip to rear tip) is responsible for areas of lift and drag spikes or drops. These plots are useful to inform which fluid slices to pay attention to to understand why drag or lift is being generated in a certain area.

Not everything listed above will be available as a POSTPRO item for your App, but please reach out to us at app-support@totalsim.us if you feel any POSTPRO item is missing for your App that will be beneficial to your analysis.