The distorted models used in the hydraulic studies are those which
- Ahave an exaggeration of the vertical scale and horizontal scale.
- Bare not geometrically similar to the prototypes.Correct
- Chave the same vertical and horizontal scale as that of the prototypes.
- Dhave the same Froude number as that for the prototypes.
Solution
Concept
Distorted Models in Hydraulic Similitude
Formula
Distortion = (Vertical scale ratio) / (Horizontal scale ratio) = (Lr)v / (Lr)h
Step-by-step solution
1. Identify the vertical scale ratio, (L\_r)\_v. 2. Identify the horizontal scale ratio, (L\_r)\_h. 3. Divide the vertical scale ratio by the horizontal scale ratio to calculate the distortion.
Explanation
A distorted model is a scaled physical model where different scale ratios are used for different directions (such as vertical and horizontal scales). Because the dimensions are scaled unequally, the shape of the model is changed and is not geometrically similar to the real structure or prototype.
Shortcut
Remember: "Distorted" = "Distorted Geometry" (unequal horizontal and vertical scales), so it is **not geometrically similar** to the prototype.
Common mistake
Students often mistakenly select Option D, assuming that hydraulic models must always follow Froude's model law and maintain Froude number similarity, without recognizing that the defining characteristic of a "distorted" model is having different vertical and horizontal scale ratios, which makes it geometrically dissimilar to the prototype.
Correct answer: B) are not geometrically similar to the prototypes.