Boundary layer heat transfer coefficients under field conditions

✍ Scribed by G.I. Pearman; H.L. Weaver; C.B. Tanner

• Publisher: Elsevier Science
• Year: 1972
• Weight: 560 KB
• Volume: 10
• Category: Article
• ISSN: 0002-1571
• DOI: 10.1016/0002-1571(72)90009-x

✦ Synopsis

Boundary layer heat transfer coefficients were measured under natural wind conditions using a transient and two steady-state methods. Measurements were made on metal disks of diameters from 1.9 to 12.7 cm above several agricultural and non-agricultural surfaces. Wind velocities varied from about 10 to 350 cm/sec. Heat transfer coefficients under natural winds averaged approximately 1.5 times greater than predicted from transfer theory for laminar flow conditions; however, the data show considerable scatter, with most estimates falling between the theoretically predicted and twice theoretically predicted values. The data were best represented by the dimensionless equation: Nu = 1.08 Pr 0.33 ReO-So There was no evidence that a correlation between the fluctuating wind velocity and fluctuating temperature gradient was responsible for significant convective heat transfer.