Morphing surfaces for the control of boundary layer transition
A structure configured to modify its surface morphology between a smooth state and a rough state in response to an applied stress. In demonstrated examples, a soft (PDMS) substrate is produced, and is pre-strained. A relatively stiff overlayer of a metal, such as chromium and gold, is applied to the substrate. When the pre-strained substrate is allowed to relax, the free surface of the stiff overlayer is forced to become distorted, yielding a free surface having a roughness of less than 1 millimeter. Repeated application and removal of the applied stress has been shown to yield reproducible changes in the morphology of the free surface. An application of such morphing free surface is to control a boundary layer transition of an aerodynamic fluid flowing over the surface.
CROSS-REFERENCE TO RELATED APPLICATIONS: This application claims priority to and the benefit of U.S. provisional patent application Ser. No. 61/130,632, filed Jun. 2, 2008, and claims priority to and the benefit of U.S. provisional patent application Ser. No. 61/196,047, filed Oct. 14, 2008, each of which applications is incorporated herein by reference in its entirety. This application is also related to U.S. patent application Ser. No. 12/106,638, filed Apr. 21, 2008, and to U.S. patent application Ser. No. 12/117,959, filed May 9, 2008.
Published - US9315259B1.pdf