Purpose

The purpose of this study is to explore the effects of aerospike and hemispherical aerodisks on flow characteristics and drag reduction in supersonic flow over a blunt body. Specifically, the study aims to analyze the impact of varying the length of the cylindrical rod in the aerospike (ranging from 0.5 to 2.0 times the diameter of the blunt body) and the diameter of the hemispherical disk (ranging from 0.25 to 0.75 times the blunt body diameter). CFD simulations were conducted at a supersonic Mach number of 2 and a Reynolds number of 2.79 × 10⁶.

Design/methodology/approach

ICEM CFD and ANSYS CFX solver were used to generate the three-dimensional flow along with its structures. The flow structure and drag coefficient were computed using Reynolds-averaged Navier–Stokes equation model. The drag reduction mechanism was also explained using the idea of dividing streamline and density contour. The performance of the aero spike length and the effect of aero disk size on the drag are investigated.

Findings

The separating shock is located in front of the blunt body, forming an effective conical shape that reduces the pressure drag acting on the blunt body. It was observed that extending the length of the spike beyond a specific critical point did not impact the flow field characteristics and had no further influence on the enhanced performance. The optimal combination of disk and spike length was determined, resulting in a substantial reduction in drag through the introduction of the aerospike and disk.

Research limitations/implications

To predict the accurate results of drag and to reduce the simulation time, a hexa grid with finer mesh structure was adopted in the simulation.

Practical implications

The blunt nose structures are primarily employed in the design of rockets, missiles, and re-entry capsules to withstand higher aerodynamic loads and aerodynamic heating.

Originality/value

For the optimized size of the aero spike, aero disk is also optimized to use the benefits of both.

中文翻译：

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超声速流经钝体时的气动尖峰和气动盘对波阻减阻的影响

目的

本研究的目的是探讨气动塞和半球形气动盘对钝体上超音速流的流动特性和减阻的影响。具体来说，该研究旨在分析改变气动塞中圆柱杆长度（范围为钝体直径的 0.5 至 2.0 倍）和半球形盘直径（范围为钝体直径的 0.25 至 0.75 倍）的影响。体直径）。CFD 模拟在超音速马赫数 2 和雷诺数 2.79 × 10 ⁶下进行。

设计/方法论/途径

ICEM CFD 和 ANSYS CFX 求解器用于生成三维流及其结构。使用雷诺平均纳维-斯托克斯方程模型计算流动结构和阻力系数。还利用划分流线和密度等值线的思想解释了减阻机理。研究了气动钉长度的性能和气动盘尺寸对阻力的影响。

发现

分离激波位于钝头体的前面，形成有效的圆锥形状，减少作用在钝头体上的压力阻力。据观察，将尖峰长度延长到超过特定临界点不会影响流场特性，并且不会进一步影响增强的性能。确定了圆盘和钉长度的最佳组合，通过引入气动钉和圆盘大大减少了阻力。

研究局限性/影响

为了准确预测阻力结果并减少仿真时间，仿真中采用了网格结构更细的六角网格。

实际影响

钝头结构主要用于火箭、导弹和重返舱的设计，以承受更高的气动载荷和气动加热。

原创性/价值

为了优化气动鞋钉的尺寸，气动盘也进行了优化，以利用两者的优点。