What is the purpose of similitude and modeling in fluid mechanics?

Conditions

• Used when assessing validity of analytical or computational solutions
• Experimental confirmation is required
• Results need only be similar, not identical

Reasoning, step by step

1. Start from an analytical solution or a computational solution (like CFD) for a flow case.
2. Ask whether the obtained result is valid.
3. Perform experiments to check whether the experimental outcome is similar to the analytical or computational result.

Example

The speaker states that if he cannot understand the behavior of the flow using an analytical solution, he uses CFD to obtain a solution, and then experiments are needed to assess whether the results are valid.

Common misconceptions

• Confusing similarity with exact equality: validation requires experimental results to match analytical or computational results exactly.
• Assuming that computational solutions (like CFD) do not need experimental validation.

Watch the explanation

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