Cara Cepat Menghitung Debit Aliran Sungai Menggunakan Current Meter

Summary

This video covers the direct measurement of river flow rate using a current meter, explaining the methodology and calculations involved. The lecturer demonstrates how to measure flow velocity at different depths, then calculates the average velocity and discharge (flow rate) using the trapezoidal formula for cross-sectional area. The example showcases how measurements at various depths (20%, 60%, and 80% of water depth) and their corresponding velocities are used to compute the flow rate. The video emphasizes the importance of accurate field measurements and provides essential formulas for calculating river discharge, offering a practical approach for students and professionals in hydrology.

Takeaways

• 😀 Measuring flow discharge in rivers can be done directly using instruments like the Kareena meter.
• 😀 Velocity in a river varies with depth, being faster near the surface and slower at the bottom.
• 😀 Measurements of velocity are taken at different depths: 0.2h, 0.6h, and 0.8h from the bottom of the river.
• 😀 At 0.2h depth, the flow velocity was measured as 0.23 m/s.
• 😀 At 0.6h depth, the flow velocity was measured as 0.19 m/s.
• 😀 At 0.8h depth, the flow velocity was measured as 0.1 m/s.
• 😀 Average velocity is calculated by averaging the velocities at different depths (V_avg = (V_1 + V_2 + V_3) / 3).
• 😀 The average velocity from the given measurements is 0.18 m/s.
• 😀 The river cross-section is assumed to be trapezoidal for calculating the flow area.
• 😀 The cross-sectional area is calculated using the formula A = (B_1 + B_2) / 2 * h, where B_1 and B_2 are the parallel sides and h is the depth.
• 😀 Flow discharge (Q) is calculated by multiplying the cross-sectional area (A) by the average velocity (V_avg), resulting in Q = A * V_avg.

Q & A

What is the main topic discussed in the script?

The main topic is how to measure the flow rate (debit) of a river or open channel using an instrument called 'Kare M' and how to apply the formula to calculate flow velocity and debit.

What are the depths measured during the river flow experiment?

The depths measured are 0.2 meters, 0.6 meters, and 0.8 meters.

How does the velocity of flow change with depth in the river?

The velocity of flow decreases as the depth increases. The flow is fastest near the surface and slows down towards the bottom of the river.

What is the formula used to calculate the average velocity of flow?

The formula used is the average of the velocities measured at different depths: V = (v_0.2 + v_0.6 + v_0.8) / 2.

What was the average velocity of flow calculated in the script?

The average velocity of flow calculated was 0.186 m/s.

How is the cross-sectional area of the river channel calculated?

The cross-sectional area is calculated using the trapezoidal formula: A = (B + B' + 2H) / 2 * H, where B is the width, B' is the opposite width, and H is the height of the channel.

What is the final debit (flow rate) of the river in the example?

The final debit, or flow rate, of the river, is 2.98 cubic meters per second.

Why is the formula for velocity divided by 2 in the calculation?

The formula averages the velocities measured at different depths to get a representative velocity across the full cross-section of the channel.

What is the significance of using the 'Kare M' instrument in this measurement process?

The 'Kare M' instrument is used to directly measure the velocity of flow at various depths in the river, which is essential for calculating the flow rate.

What does the script suggest about the shape of the river channel?

The script assumes the river channel has a trapezoidal shape, which is used to calculate the cross-sectional area for the flow rate calculation.