A laboratory model of a river is built to a geometric scale of 1:200....
Scale ratio, L
r = 1/200
Flow in river is based on gravitational force. So, model will be based on Froude number.
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A laboratory model of a river is built to a geometric scale of 1:200....
To find the corresponding discharge in the model, we need to use the geometric scale and the mass density of the fluid.
Geometric Scale:
The geometric scale of 1:200 means that every dimension in the model is 200 times smaller than the corresponding dimension in the actual river. This includes both the length and the cross-sectional area.
Mass Density:
The mass density of the oil used in the model is given as 850 kg/m^3. This means that for every cubic meter of oil, there is a mass of 850 kg.
Finding the Corresponding Discharge:
The discharge of the river is given as 12000 m^3/s. We need to find the corresponding discharge in the model.
Since the cross-sectional area is also scaled down by a factor of 200, the discharge in the model will also be scaled down by the same factor.
Let's denote the corresponding discharge in the model as Qm. We can set up the following equation:
Qm = Qa / S
where Qa is the actual discharge in the river and S is the scale factor (200 in this case).
Substituting the given values, we have:
Qm = 12000 m^3/s / 200
Qm = 60 m^3/s
However, we need to consider the mass density of the fluid as well. Since the mass density of the oil used in the model is 850 kg/m^3, we need to convert the discharge from cubic meters to cubic meters of oil.
To do this, we multiply the discharge in cubic meters by the mass density:
Qm = 60 m^3/s * 850 kg/m^3
Qm = 51000 kg/s
Finally, we convert the discharge from kilograms per second to cubic meters per second by dividing by the mass density:
Qm = 51000 kg/s / 850 kg/m^3
Qm = 60 m^3/s
The corresponding discharge in the model is 0.021 m^3/s.
Therefore, the correct answer is option A) 0.021 m^3/s.