## Find and Compare Strouhal Numbers

## Work Time

# Find and Compare Strouhal Numbers

To calculate the Strouhal number, you multiply the wing-flap frequency by the distance between the tip of the wing at its highest and lowest points, and then divide the result by the animal’s cruising speed.

Use the data in the table and the problem-solving process to answer these questions.

- What is the Strouhal number for the hummingbird?
- What is the Strouhal number for the albatross?
- How do these two numbers compare?

Begin by writing a formula for calculating the Strouhal number for any bird. To help you write this formula, ask yourself:

- What are the variables in the problem?
- How are the variables related?
- What information about Strouhal numbers is given? How can you use this information?
- What mathematical operations do you need to include in your formula?