The discussion revolves around determining the dynamic viscosity of air in the context of an airfoil flying at a specific speed under sea-level conditions. The original poster presents a scenario involving known parameters such as air density and length, while expressing confusion regarding the relationship between dynamic viscosity and Reynolds number.
The discussion is ongoing, with participants raising questions about the assumptions regarding viscosity's dependence on temperature and velocity. Some guidance has been offered regarding the nature of viscosity as a property of air, but no consensus has been reached on the implications for the problem at hand.
Participants note the importance of temperature in determining dynamic viscosity, referencing standard sea-level conditions. There is an acknowledgment of the need for specific information regarding temperature to proceed with calculations.
What is the temperature? You are aware that, under these conditions, the dynamic viscosity (a physical property of the air) is a unique function of temperature that you can look up on line, right?Angelina21 said:Homework Statement
Considering an airfoil (a flat plate) flying at 100 m/s under sea-level conditions, so the density is 1.225 kg/m3 and the length being 1 m, what is the dynamic viscosity of air? The problem is that I have two variables in one formula, Reynolds number and the viscosity.
Homework Equations
Dynamic viscosity=(density*velocity*length)/Re
The Attempt at a Solution
The temperature according to sea level conditions is 15oC. I'm aware that it's online. But doesn't the viscosity depend on velocity? Or it's always constant, no matter the velocity?Chestermiller said:What is the temperature? You are aware that, under these conditions, the dynamic viscosity (a physical property of the air) is a unique function of temperature that you can look up on line, right?
Like I said, it's a physical property of the air, independent of anything being done to the air.Angelina21 said:The temperature according to sea level conditions is 15oC. I'm aware that it's online. But doesn't the viscosity depend on velocity? Or it's always constant, no matter the velocity?