Retractable strake and method

Abstract

A retractable strake is disclosed that includes an assembly of flexible finger elements or flexible faces. The assembly, when coupled to a structure, deflect at wind speeds greater than approximately twenty mph or wind pressures greater than approximately one psf. Accordingly, the strakes' retractable or flexing feature does not contribute to the wind load when the wind load is overly severe, while providing vortex shedding benefits within a wind speed profile range.

What is claimed is:  
     
         1 . A system for reducing vortex shedding on an object, comprising: 
 a strake having a substantially polygonal shape; and    flexible attachment feet, wherein the strake is attached to the feet and the feet are attached to the object.    
     
     
         2 . The system of  claim 1 , wherein the strake deflects at wind pressures greater than approximately one psf.  
     
     
         3 . The system of  claim 1 , wherein the strake deflects at wind speeds greater than approximately twenty mph.  
     
     
         4 . The system of  claim 1 , wherein the strake's inner edge is notched.  
     
     
         5 . The system of  claim 1 , wherein the strake is attached to the object by a single foot.  
     
     
         6 . The system of  claim 1 , wherein the strake is substantially rectangular.  
     
     
         7 . The system of  claim 1 , further comprising: 
 a plurality of strakes, the plurality of strakes being arranged about the object in a semi-helical form.    
     
     
         8 . The system of  claim 1 , wherein the plurality of strakes are arranged about the object in a plurality of semi-helical forms.  
     
     
         9 . The system of  claim 1 , wherein the strake is molded to the feet.  
     
     
         10 . The system of  claim 1 , wherein the feet are molded into the object.  
     
     
         11 . The system of  claim 1 , wherein the strake is less than five inches wide.  
     
     
         12 . The system of  claim 1 , wherein a maximum height of the strake is approximately 10 percent of an overall diameter of the object.  
     
     
         13 . The system of  claim 1 , wherein a surface of the strake is patterned.  
     
     
         14 . The system of  claim 1 , wherein the object is a radome.  
     
     
         15 . The system of  claim 1 , wherein the object is a chimney.  
     
     
         16 . The system of  claim 1 , wherein the object is a mast.  
     
     
         17 . The system of  claim 7 , wherein the strakes of the plurality of strakes are displaced from each other by approximately {fraction (1/2)} inches.  
     
     
         18 . An apparatus for reducing vortex shedding on an object, comprising: 
 vortex shedding means for shedding vortices about the object, wherein the shedding means is flexibly retractable; and    attachment means for attaching the vortex shedding means to the object, wherein at least one of the vortex shedding means or the attachment means flexs when at least one of wind speeds are greater than approximately twenty mph and wind pressures are greater than approximately one psf.    
     
     
         19 . The apparatus of  claim 17 , wherein the shedding means and the attachment means are positioned in a semi-helical arrangement about the surface of the object.  
     
     
         20 . The apparatus of  claim 18 , wherein the attachment means is an adhesive.  
     
     
         21 . The apparatus of claim;  18 , wherein the shedding means is primarily a truncated flat surface.  
     
     
         22 . The apparatus of  claim 18 , wherein the object is a radome.  
     
     
         23 . A method for manufacturing an apparatus for reducing vortex shedding on an object, comprising: 
 arranging a plurality of truncated two-side strake elements into an assembly of attachment elements; and    coupling the assembly of attachment elements to the object, such that the assembly of strake elements deflects when at least one of wind speeds are greater than approximately twenty mph and wind pressures are greater than one psf.