Drag Difference Between Skier and Snowboarder

May 3, 2022 Tony Ronald

Introduction

Everyone can agree that skiers are faster down the mountain than snowboarders, but how much faster?  This article will look at the drag difference between the two styles.  The skier has a big advantage facing forward in that it can decrease its frontal projected area (area projected onto a plane) by bending at the knees and waist while the snowboarder’s area remains constant whether the knees and waist are bent or not.  In this model, the skier has a frontal area of about 3.0 ft2 while the snowboarder is 3.78 ft2.

Image1Image2Figure 1: Frontal Area

Results

A CFD analysis was set up to compare the drag between the two different positions up to 60 MPH.  Figure 1 below shows the high-pressure areas of each person.  The snowboarder has a more high-pressure area than the skier.  This creates the majority of the drag force (the other component is skin friction).

Image4
Image4
Image4

Figure 2: Static Pressure (Gauge)

Figure 4 shows the drag over a range of airspeeds.  At all wind speeds, the snowboarder has about 2x the total drag of the skier.  A cause of the snowboarder’s higher drag is due to the inability to reduce his frontal area. However, the main cause for higher drag is that the snowboarder also has a vertical/flat surface (high drag coefficient) that is not very aerodynamic compared to the skier (see Figure 3).  There is not much that can be done to help the snowboarder become more aerodynamic. 

Image7
Image7

Figure 3: Side View Showing Aerodynamic Shape

Figure 4 table

Figure 4: Drag vs Speed

Other than just comparing the total drag force, another way to compare the two shapes is by drag coefficients.  This is essentially a drag efficiency that normalizes the drag forces and compares the pressure force so that the frontal area can be ignored.  The snowboarder has a drag coefficient of 0.85 while the skier is 0.59 (an increase of about 45%).  So even with a similar frontal area, the snowboarder would still have more drag than the skier (due to the inability to create an aerodynamic shape). 

Image9
Image9

Figure 5: Two Snowboarders at Aspen, CO (the one in black may or may not be me)

 

About the Author

CFD Simulation Specialist

More Content by Tony Ronald
Previous Article
Transient Effects of Solar Radiation
Transient Effects of Solar Radiation

Spring has officially arrived promising warmer temperatures and a higher probability of seeing the sun. The...

Next Article
Efficiencies of the Object Generator
Efficiencies of the Object Generator

The model chosen to demonstrate some of the advantages of using Ansys Object Generator is shown below. It c...

Get Ansys Tips Delivered to Your Inbox

Sign Up