What is the relationship between y_c and y_R in fluid mechanics?

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In summary, the calculation of yR in fluid mechanics involves determining the hydrostatic force on a plane surface. The equation for yR is yc + (I_xc / (y_c * A)), where yc is the centroid of the gate and yR is the resultant of pressure acting on the gate. This information can be found in Fundamentals of Fluid Mechanics (6th Ed.) by Munson, and a detailed derivation and example calculation can be found in the article (pp. 6-8) provided.
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Homework Statement



During the calculation of yR in fluid mechanics problem, hydrostatic force on a plane surface

Homework Equations



yR = yc+[itex]\frac{I_xc}{y_c×A}[/itex]

The Attempt at a Solution



I can see how it is calculated but I've read through the chapter and I don't see how it is described. The textbook is Fundamentals of Fluid Mechanics (6th Ed.) by Munson.
 

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It looks like yc is the location of the centroid of the gate, while yR is the location of the resultant of the pressure acting on the gate, or the center of pressure.

This article (pp. 6-8) gives the derivation and an example calculation:
http://www.freestudy.co.uk/fluid mechanics h1/outcome11.pdf
 
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FAQ: What is the relationship between y_c and y_R in fluid mechanics?

What is y_c when finding y_R?

Y_c refers to the centroid of a shape, which is the point at which the shape would balance perfectly if it were to be cut out of a sheet of material. When finding y_R, which refers to the distance from the neutral axis to the farthest point on the shape, y_c is used in the calculation.

How is y_c determined?

Y_c is determined by finding the average of the y-coordinates of all the points that make up the shape. This can be done by dividing the sum of all the y-coordinates by the total number of points.

Why is y_c important in finding y_R?

Y_c is important because it is used in the calculation of the moment of inertia, which is a measure of an object's resistance to changes in rotation. Y_R, which is the distance from the neutral axis to the farthest point on the shape, is a key component in the moment of inertia calculation.

Can y_c be negative?

Yes, y_c can be negative if the shape has points with negative y-coordinates. This typically occurs when the shape is not symmetrical or when the origin of the coordinate system is not at the centroid.

How does y_c affect the final calculation of y_R?

Y_c affects the final calculation of y_R because it is used in the equation to determine the moment of inertia. The moment of inertia, along with other factors such as material properties and applied loads, ultimately determines the value of y_R.

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