What is Hardy-Cross method used for in hydraulics?

• A. An iterative method to balance flows in looped pipe networks so that energy losses and continuity are satisfied
• B. A direct algebraic method to solve for flows
• C. A method to compute head losses in a single pipe
• D. A method to optimize pump energy usage

Answer: (A)

The Hardy-Cross method is used to find how much flow goes through each pipe in a network that has loops, by iteratively balancing the energy losses around each loop while also satisfying mass conservation at the junctions. You start with a guess for the flow in every pipe, calculate the head losses, and look at each loop to see how far the loop’s head-loss sum is from zero. A loop correction is then computed and distributed among the pipes in that loop according to their hydraulic resistances, and you update the pipe flows. Repeating this process until the loop sums and the node balances converge gives a consistent set of flows that satisfy both the energy (head loss) and continuity conditions. This is inherently iterative and specifically aimed at looped networks, not a direct algebraic solution for a single pipe or an optimization of pump energy.