Distorted Models

DISTORTED MODELS:

A model which is not geometrically similar to its prototype is known as distorted models.

Distorted model is one which has its one or more characteristics not similar to the corresponding characteristics of prototype. A model having different horizontal and vertical scale ratio is a distorted model.

In order to predict the performance of prototype, the law of distortion have to be applied to the results obtained from the model test.

Following are the Distortions may be Introduced in a Model.

(a) Geometric distortion.

This distortion results due to adoption of different scale for vertical and horizontal dimensions.

(b) Configuration distortion.

The model is geometrically similar but its bed slope in increased by keeping it in a tilted position compared to the position of the prototype.

(c) Hydraulic distortion.

This distortion occurs due to a charge in some hydraulic quantity such as velocity (or) discharge.

(d) Material distortion.

This distortion involves the use of different materials for the model and prototype. 

1. Merits of Distorted Models:

(i) Model size can be sufficiently reduced and construction cost is savings.

(ii) Operation can be simplified by model in small size.

(iii) Accurate measurements are made easily due to increase in the depth of fluid (or) height of waves.

(iv) An increase the flow rate can be obtained and that will yield better results.

(v) The effects of surface tension can be reduced to minimum.

2. Demerits of Distorted Models:

(i) Slopes, bends and cuts can't be reduced

(ii) Depth distortion gives rise to different wave pattern.

(iii) Unfavorable psychological effect on the observer.

(iv) Results obtained from distorted models are difficult.