[amp_mcq option1=”0″ option2=”$$\\frac{{\\text{r}}}{2}$$” option3=”r” option4=”2r” correct=”option1″]<\/p>\n
The correct answer is $\\frac{{\\text{r}}}{2}$.<\/p>\n
The boundary layer is a thin layer of fluid in the immediate vicinity of a solid surface where the fluid velocity changes from zero at the surface to the free stream velocity at a distance of the order of the boundary layer thickness.<\/p>\n
The boundary layer thickness is defined as the distance from the surface where the fluid velocity reaches 99% of the free stream velocity.<\/p>\n
In a pipe of radius $r$, the maximum thickness of the boundary layer occurs at the pipe wall and is given by:<\/p>\n
$$\\delta = \\frac{{\\text{r}}}{2}$$<\/p>\n
The other options are incorrect because they are either too small or too large. Option A is incorrect because the boundary layer thickness cannot be zero. Option C is incorrect because the boundary layer thickness cannot be equal to the pipe radius. Option D is incorrect because the boundary layer thickness cannot be twice the pipe radius.<\/p>\n","protected":false},"excerpt":{"rendered":"
[amp_mcq option1=”0″ option2=”$$\\frac{{\\text{r}}}{2}$$” option3=”r” option4=”2r” correct=”option1″]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[648],"tags":[],"class_list":["post-7296","post","type-post","status-publish","format-standard","hentry","category-hydraulics-and-fluid-mechanics","no-featured-image-padding"],"yoast_head":"\n