Hydrodynamic and Thermal Boundary Layer

What is the main difference between the hydrodynamic and thermal boundary layer?

• Hydrodynamic boundary layer is related to fluid velocity while thermal boundary layer is related to temperature gradient
• Hydrodynamic boundary layer is related to temperature gradient while thermal boundary layer is related to fluid velocity
• Both are related to fluid velocity
• Both are related to temperature gradient

What type of convection involves flow over plates and cylinders?

• Forced convection only
• Free convection only
• Both forced and free convection
• None of the above

What is the boundary layer?

• The layer of fluid in direct contact with the solid boundary
• The layer of fluid that experiences the highest velocity in a flow
• The layer of fluid that experiences the lowest velocity in a flow
• The layer of fluid that has the highest pressure in a flow

How does increasing the Reynolds number affect the thickness of the boundary layer in forced convection?

• The boundary layer thickness decreases
• The boundary layer thickness increases
• The boundary layer thickness remains the same
• None of the above

Which of the following statements is true for thermal boundary layer?

• It is thinner than hydrodynamic boundary layer
• It is thicker than hydrodynamic boundary layer
• Its thickness is same as hydrodynamic boundary layer
• Its thickness cannot be predicted

Which of the following is true for internal flow through tubes?

• The thickness of the boundary layer increases along the length of the tube
• The thickness of the boundary layer decreases along the length of the tube
• The thickness of the boundary layer remains constant along the length of the tube
• None of the above

A fluid is flowing over a cylinder. What type of flow is this an example of?

• Free convection
• Forced convection
• Mixed convection
• None of the above

What is the effect of increasing the temperature of a fluid on the thermal boundary layer thickness?

• The thickness of the thermal boundary layer increases
• The thickness of the thermal boundary layer decreases
• The thickness of the thermal boundary layer remains the same
• None of the above

A fluid is flowing through a tube. What type of flow is this an example of?

• Free convection
• Forced convection
• Mixed convection
• None of the above