Flow Rate Calculator
Understanding Flow Rate
Flow rate, often denoted by Q, is a fundamental concept in fluid dynamics and engineering. It represents the volume of fluid that passes through a given surface per unit of time. The standard SI unit for flow rate is cubic meters per second (m³/s).
The calculation for flow rate is straightforward when you know the cross-sectional area through which the fluid is flowing and the average velocity of the fluid across that area.
The formula is:
Q = A × v
Where:
- Q is the flow rate
- A is the cross-sectional area
- v is the average velocity
To use this calculator, you need to provide the cross-sectional area of the flow path (e.g., the cross-section of a pipe or channel) and the average speed at which the fluid is moving through that area. Ensure that the units for area and velocity are consistent or that the calculator can handle conversions internally. This calculator supports common units for area (square meters, square centimeters, square inches, square feet) and velocity (meters per second, centimeters per second, inches per second, feet per second).
For example, if a pipe has an internal cross-sectional area of 0.1 square meters (m²) and the fluid inside is flowing at an average velocity of 3 meters per second (m/s), the flow rate would be Q = 0.1 m² × 3 m/s = 0.3 m³/s.
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function calculateFlowRate() {
var areaInput = document.getElementById("area");
var velocityInput = document.getElementById("velocity");
var area = parseFloat(areaInput.value);
var velocity = parseFloat(velocityInput.value);
var areaUnit = document.getElementById("areaUnit").value;
var velocityUnit = document.getElementById("velocityUnit").value;
var resultDiv = document.getElementById("result");
resultDiv.style.color = "#28a745"; // Default success color
if (isNaN(area) || isNaN(velocity)) {
resultDiv.innerHTML = "Please enter valid numbers for Area and Velocity.";
resultDiv.style.color = "red";
return;
}
if (area <= 0 || velocity <= 0) {
resultDiv.innerHTML = "Area and Velocity must be positive values.";
resultDiv.style.color = "red";
return;
}
// Unit conversion logic to a common base (e.g., meters and seconds)
var baseArea = area;
if (areaUnit === "cm2") {
baseArea = area / 10000; // cm^2 to m^2
} else if (areaUnit === "in2") {
baseArea = area * 0.00064516; // in^2 to m^2
} else if (areaUnit === "ft2") {
baseArea = area * 0.092903; // ft^2 to m^2
}
var baseVelocity = velocity;
if (velocityUnit === "cms") {
baseVelocity = velocity / 100; // cm/s to m/s
} else if (velocityUnit === "ips") {
baseVelocity = velocity * 0.0254; // in/s to m/s
} else if (velocityUnit === "fps") {
baseVelocity = velocity * 0.3048; // ft/s to m/s
}
// Calculate flow rate in m³/s
var flowRate_m3ps = baseArea * baseVelocity;
// Display result in m³/s as it's the standard SI unit.
resultDiv.innerHTML = "Flow Rate (Q): " + flowRate_m3ps.toFixed(6) + " m³/s";
}