用多保真度方法减少高成本仿真,精准预测气动性能不确定性。
Uncertainty Quantification for Multi-fidelity Simulations
- 结合高/低保真度仿真数据,用深度神经网络融合建模。
- 在1~100维测试中,模型精度优于克里金法,32维以上仍有效。
- 适合需要高效不确定性分析的工程仿真场景,尤其资源受限时。
研究基于Nektar++(基于应用数学的求解器)和XFOIL分别获取高保真与低保真数值模拟数据。采用更高阶多项式分布计算升力与阻力系数,显著提升精度与准确性。通过协同克里金数据融合与自适应采样技术,在不依赖高性能计算集群的前提下,实现了对有限域内升力与阻力的精确预测,构建了降低样本需求的计算流体动力学不确定性量化方法。为减少对高保真数值模拟的依赖,提出多保真度策略。多保真度深度神经网络模型在1、32和100维基准函数逼近任务中表现优异,涵盖线性与非线性相关性,其性能超越协同克里金方法。该模型还成功模拟了输入不确定性(均匀与高斯分布)下1、32和100维函数的随机传播,高效预测了关注量的概率密度分布及统计矩。相比之下,协同克里金模型在32维以上因内存存储与操作限制而表现受限。
原文摘要 · Abstract (English)
The work focuses on gathering high-fidelity and low-fidelity numerical simulations data using Nektar++ (Solver based on Applied Mathematics) and XFOIL respectively. The utilization of the higher polynomial distribution in calculating the Coefficient of lift and drag has demonstrated superior accuracy and precision. Further, Co-kriging Data fusion and Adaptive sampling technique has been used to obtain the precise data predictions for the lift and drag within the confined domain without conducting the costly simulations on HPC clusters. This creates a methodology to quantifying uncertainty in computational fluid dynamics by minimizing the required number of samples. To minimize the reliability on high-fidelity numerical simulations in Uncertainty Quantification, a multi-fidelity strategy has been adopted. The effectiveness of the multi-fidelity deep neural network model has been validated through the approximation of benchmark functions across 1-, 32-, and 100-dimensional, encompassing both linear and nonlinear correlations. The surrogate modelling results showed that multi-fidelity deep neural network model has shown excellent approximation capabilities for the test functions and multi-fidelity deep neural network method has outperformed Co-kriging in effectiveness. In addition to that, multi-fidelity deep neural network model is utilized for the simulation of aleatory uncertainty propagation in 1-, 32-, and 100 dimensional function test, considering both uniform and Gaussian distributions for input uncertainties. The results have shown that multi-fidelity deep neural network model has efficiently predicted the probability density distributions of quantities of interest as well as the statistical moments with precision and accuracy. The Co-Kriging model has exhibited limitations when addressing 32-Dimension problems due to the limitation of memory capacity for storage and manipulation.
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