![]() Such physics-based semi-empirical model can be used for a wide range of turbofans. Additionally, a semi-empirical turbofan thrust model usable for a wide range of bypass ratios and the entire flight envelope was developed. Other novel features of this article include a new semi-empirical fuel-flow law, which was also extensively tested. ![]() ![]() This guess resulted in fast quadratic convergence in all computations. A methodology for an initial guess was developed starting with the maximum-range cruise Mach without the wave-drag included. The NR method was first tested for accuracy and convergence using known analytical solutions. Numerical Newton–Raphson nonlinear solvers were used to find real positive roots of such polynomials. The resulting nonlinear equations are of 12th- and 13th-order. For maximum range cruise estimations, an optimization criterion based on maximizing specific air range was used. In this study, a new semi-empirical transonic wave drag model using modified Lock’s equation was developed. In the initial design phase and later when the preliminary wind-tunnel and/or CFD computations and drag polars are known with increased accuracy, a method of estimating cruise performance is needed. ![]() Modern jet airplanes cruise most efficiently in the vicinity of the drag-divergence or drag-rise Mach numbers. One of the most difficult steps in estimating the cruise performance characteristics of high-subsonic transport-category turbofan-powered airplanes is the estimation of the transonic wave drag.
0 Comments
Leave a Reply. |