What do your results mean?

Overview

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

Contents of Page:

Variables

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

Table 1: Variable descriptions

The coefficients are normalized by freestream dynamic pressure. Dynamic pressure is equal to the one half of the fluid density and freestream velocity, shown in equation 1.

Equation 1: Force Coefficient

Cf includes an additional set of images and movies with LIC. "LIC", short for line integral convultion, is surface streamlines overlaid on the surface to indicate the vector orientation of the local shear-stress. This is analogous to oil flow visualization done in wind tunnels, test flights or track tests.

Images

Cp Plots

Image 1: Vehicle front end - Cp

Image 2: Vehicle rear end - Cp

The Cp plots above shows a positive Cp on the front of the vehicle and a negative Cp on the rear of the vehicle. The front and rear end are both drag contributors . Positive pressure at the front tends to generate drag and negative pressure at the rear also generates drag.

CpX Plots

Image 3: Vehicle front end - CpX

Image 4: Vehicle rear end - CpX

CpX plots isolate the pressure effects in the longitudinal direction and show how the pressure is creating drag. Values above zero (warmer colors) show drag while values below zero (cooler colors) show thrust. The view above is the front and rear of the vehicle. From the images above it shows that the front end has a high CpX (drag contributing) and the front end has a low CpX (drag reducing). Low pressure on rear-facing surfaces tend to suck the vehicle backwards which integrates into drag.

CpY

Image 5: Vehicle right hand side - CpY

Image 6: Vehicle left hand side - CpY

CpY plot isolates the pressure effects that create the sideforce. Here the colors show the direction the sideforce is acting, with reds and yellows showing forces acting to the right (de-stabilizing) and blues and purples to the left (stabilizing) as the driver sees them. 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. As the flow accelerates around the nose 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.

CpZ Plots

Image 7: Vehicle top view - CpZ

Image 8: Vehicle botttom view - CpZ

In the the CpZ plots above, the forces are summed in the z-direction. Low CpZ equates to regions of downforce (negative lift) while high CpZ equates to regions of lift. The plots above show large regions of downforce on the bottom surface of the vehicle. The front wing experiences downforce on the bottom surface of the wing while the rear wing There are small regions of lift located on the suspension and body.

XRay Plots

Image 9: Drag Xray plots

Image 10: Lift Xray plots

Image 11:Side Force Xray plots

These plots show the summation of the Downforce/Lift or Drag. The sum of all forces on Xray plots will be equal to the drag or downforce reported in the app. The Xray images display the hot spot of force generation. Each pixel is the total force along that axis from the front to rear of the car. This will give you a good sense as to which areas on the vehicle are more beneficial or detrimental to downforce/lift or drag. The Lift Xray plot above shows the downforce generation on the front and rear wing along with downforce production toward the rear of the vehicle. While drag is observed on the front and rear wheels of the car.

Accumulation Plots

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.

Image 9: Vehicle span drag accumulation

Image 10: Vehicle span lift accumulation

Movies

The TS AUTO APP creates animations showing the flow progression along the span of the video. Movies are created in the X, Y, and Z direction. The movie to the right shows the velocity contours in the Y direction.

Velocity contour movie in the y direction