Blended Wing Body Unmanned Aerial Vehicle Research Articles

Optimization of a Blended-Wing-Body Unmanned Aerial Vehicle Design for Maximum Aerodynamic Lift-to-Drag Ratio

Although unmanned aerial vehicle (UAV) has found many applications in various fields, its operation has been constrained by its low flight endurance. To date, several design efforts are pursued to improve this performance and one of them is the exploration of blended-wing-body (BWB) design. In this study, parametric study is conducted on the BWB UAV design of Baseline-VII that is developed by Flight Technology and Test Center (FTTC), Universiti Teknologi MARA Shah Alam, Malaysia. The primary goal is to optimize the current Baseline-VII design for maximum lift-to-drag ratio, which in turn implies a higher flight endurance. Three design parameters are considered: inboard wing sweep angle, outboard wing sweep angle and also inboard wing span. A full-factorial design of experiments (DoE) is applied to set the total 27 design case settings for this study, with three different values considered for each design parameter: 10°, 25° and 50° for inboard and outboard wing sweep angles, and 200 mm, 300 mm and 400 mm for the inboard wing span. The computer-aided design (CAD) models for the design cases are constructed using Solidworks and the resultant aerodynamic lift-to-drag ratio is found through computational fluid dynamics (CFD) simulation analysis using ANSYS Fluent. The collected data is then statistically analysed using regression analysis in MINITAB to construct a representative regression model that aptly capture the effects of the varied design parameters on the design aerodynamic lift-to-drag ratio. Based on the results, it has been found that the maximum lift-to-drag ratio for the modified Baseline-VII UAV design is 2.8119, which is obtained with optimal settings of inboard wing sweep angle = 17.2727°, outboard wing sweep angle = 20.9091° and inboard wing span = 400 mm. This is about 28.4% increment of lift-to-drag ratio from the original Baseline-VII design.

Numerical investigation of the impact of tubercles and wing fences on the aerodynamic behaviour of a fixed-wing, tactical Blended-Wing-Body UAV platform

In this work, a study on the impact of passive flow control techniques on an Unmanned Aerial Vehicle (UAV) Blended Wing Body (BWB) is presented. The novel BWB layout integrates smoothly the wing to the fuselage, creating an aerodynamically superior platform. However, the lack of vertical stabilizers in the form of a tail, creates the need for aerodynamically stable and efficient wings that can withstand the spanwise flow. To that end, two passive flow control techniques are implemented in this study, namely the wing fences and the tubercles. Wing fences are vanes or airfoils attached vertically to the lifting surface and are one of the oldest flow control techniques used in aerospace applications to stop the spanwise flow. Wing fences extending from the leading edge to the trailing edge completely stop the spanwise flow. On the other hand, tubercles are sinusoidal modifications of the blade’s leading edge. This is a novel flow control technique, with the original concept inspired from the characteristic flipper of the humpback whale (Megaptera Novaeangliae). Each bump creates a set of counter-rotating vortices that acts as a virtual fence and stops the spanwise flow. The results from this comparison show that flow control techniques can offer a considerable benefit to the flying capabilities of a BWB UAV platform, by improving the lift distribution and increasing the maximum coefficient of lift.

Preliminary design of a BWB UAV for highway traffic monitoring

The current work presents the preliminary design procedure of a small-scale, fixed-wing Unmanned Aerial Vehicle (UAV), incorporating the novel Blended-Wing-Body (BWB) layout configuration. The UAV is designed to support a Cooperative-Intelligent Transport System (C-ITS), for monitoring traffic conditions at large national highways. The presented UAV design procedure emphasizes on both aerodynamic and stability behavior, aiming to a high aerodynamic efficiency and the satisfaction of the mission requirements. The design is supported by CFD analyses, to determine the aerodynamic and stability coefficients. Following the CFD modeling, the performance parameters of the platform are calculated. Furthermore, an internal layout study is conducted to integrate all the necessary internal components, determining the center of gravity. Finally, the overall UAV design concludes to an optimum configuration of the UAV-ITS, satisfying all the aerodynamic, stability and mission requirements.

Modal Analysis Of Blended Wing-Body UAV

The modal analysis deals with the dynamic behavior of mechanical structures under the dynamic vibration. This study aims to analyze the vibration characteristic of the blended wing-body Unmanned Aerial Vehicle (UAV) using modal analysis. The numerical method is used to calculate the eigen frequencies of the system. The COMSOL Multiphysics is selected as the Finite Element Method (FEM) software to simulate the study. The resulted eigen frequencies are 278.05 Hz, 721.28 Hz, 816.39 Hz, 1601.7 Hz, 1699.5 Hz, and 1855.5 Hz. The study also evaluates the displacement of the leading edge of the wing in all axes to understand the modal shapes. The modal shapes found are updrift, swift back, flapping vertical, flapping horizontal, flapping opposite horizontal and flapping more wave in horizontal movement. The comparison of resulted eigen frequencies with a conventional aircraft wing is conducted to understand the difference in its vibration characteristics.

Aero-structural numerical analysis of a blended wing body unmanned aerial vehicle using a jute-based composite material

Research and development of biocomposites for Unmanned Aerial Vehicle (UAV) structures have become relevant throughout the last decade, due to their cost and lightweight accompanied with good mechanical properties. Moreover, Blended Wing Body configurations (BWB) have aroused special interest, because of their aerodynamic efficiency, manufacturing simplicity and increased fuel economy. In this context, the present study investigates the strength distribution in a semi-monocoque structure of a blended wing body UAV using a composite material based on pre-load jute fibers. For this aim, a three-dimensional numerical simulation with a unidirectional fluid–solid coupling is implemented in a steady analysis at cruise conditions. The air pressure distribution is calculated using computational fluids dynamics (CFD), which then incorporates the aerodynamic loads within the structural module and using finite element method (FEM) determines the static stress distribution and deformation. The properties and manufacturing characteristics of jute-based composite material used in the numerical analysis were incorporated in the analysis and the numerical model was validated against experimental data. Based on the comparison between the structure built by pre-load jute fibers-based composite material and EPO foam, the results show that the proposed material reduces the deformation in 65% and performs better mechanically.

Quasi-3D Aerodynamic Analysis Method for Blended-Wing-Body UAV Configurations

The current study presents a low-fidelity, quasi-3D aerodynamic analysis method for Blended-Wing-Body (BWB) Unmanned Aerial Vehicle (UAV) configurations. A tactical BWB UAV experimental prototype is used as a reference platform. The method utilizes 2D panel method analyses and theoretical aerodynamic calculations to rapidly compute lift and pitching moment coefficients. The philosophy and the underlying theoretical and semi-empirical equations of the proposed method are extensively described. Corrections related to control surfaces deflection and ground effect are also suggested, so that the BWB pitching stability and trimming calculations can be supported. The method is validated against low-fidelity 3D aerodynamic analysis methods and high-fidelity, Computational Fluid Dynamics (CFD) results for various BWB configurations. The validation procedures show that the proposed method is considerably more accurate than existing low-fidelity ones, can provide predictions for both lift and pitching moment coefficients and requires far less computational resources and time when compared to CFD modeling. Hence, it can serve as a valuable aerodynamics and stability analysis tool for BWB UAV configurations.

Cooling system design for the internal combustion engine of a BWB UAV prototype

The current study presents an analytical design methodology for a compact thermal management system (cooling system) of a high-power density internal combustion rotary engine. The engine is installed on a fixed wing, tactical Blended-Wing-Body (BWB) Unmanned Aerial Vehicle (UAV) prototype that has been developed for the aerial delivery of cargo and lifesaving supplies. The design methodology is based mainly on a low-fidelity thermodynamic model and on high-fidelity Computational Fluid Dynamics (CFD) analyses. The results are validated against wind tunnel experiments for the cooling system of the engine. The overall methodology is divided into two distinct segments, the design of the heat exchanger (HEX) and the sizing of the cold-air inlet ducts. The low-fidelity thermodynamic model is based on 0D and 1D textbook methods and well-established formulae from the existing literature. The thermodynamic model is used for the calculation of the geometrical characteristics of the HEX. The high-fidelity CFD modeling is employed to yield a more detailed investigation of the flow field around the HEX and provide information about whether the airflow velocity requirements, for the 0D and 1D model, are met. Additionally, the detailed CFD computations assist the design of high-efficiency inlet ducts, in order to secure optimal airflow through the HEX and around the engine compartment. Using the proposed methodology, a functional HEX experimental prototype is designed and manufactured, as a proof of concept, in order to be thoroughly examined on a test rig in laboratory conditions. Multiple experiments are conducted in a variety of inlet temperatures and airflow velocities, for the validation and fine-tuning of the overall proposed design methodology. The study concludes with the final HEX design, as well as an analysis of its integration aspects on the tactical BWB UAV prototype.

EXPERIMENTAL ANALYSIS OF BLENDED WING BODY MODEL MICRO AIR VEHICLE USING WIND TUNNEL

An experimental aerodynamic analysis is performed to obtain aerodynamic characteristics and performance of a blended wing-body aircraft (BWB) using Low Speed Wind Tunnel. The BWB design concept is a revolutionary way of understanding the hike of fuel cost, increase in air travelers and environmental concern. Recognizing the potential of the aircraft an experimental analysis is conducted on BWB to understand aerodynamic performance parameters like lift coefficient (CL), drag coefficient (CD) and the Lift-to-Drag (L/D) ratio .The aluminium BWB model is manufactured using CNC machine and is tested in Wind tunnel at different angle of attack varying from 0° to 16° at speed of 12 m/s ,25 m/s and 35 m/s velocity. The present BWB UAV design has achieved an unprecedented capability in terms of sustainability of flight at high angle of attack, low parasite drag coefficient and decent maximum lift coefficient. This study indicates some significant benefits for the BWB relative to the conventional aircraft configuration. KEYWORDS: Blended Wing Body (BWB), Aerodynamics, Unmanned Aerial Vehicle (UAV), Wind Tunnel

Aerodynamic Analysis of Blended Wing Body - Unmanned Aerial Vehicle (BWB-UAV) Equipped with Horizontal Stabilizers

This paper presents an aerodynamic characteristic study in longitudinal direction of UiTM Blended Wing Body-Unmanned Aerial Vehicle Prototype (BWB-UAV Prototype) equipped with horizontal stabilizers. Flight tests have been conducted and as the result, BWB experienced overturning condition at certain angle of attack. Horizontal stabilizer was added at different location and size to overcome the issue during the flight test. Therefore, Computational Fluid Dynamics (CFD) analysis is performed at different configuration of horizontal stabilizer using Spalart - Allmaras as a turbulence model. CFD simulation of the aircraft is conducted at Mach number 0.06 or v = 20 m/s at various angle of attack, α. The data of lift coefficient (CL), drag coefficient (CD), and pitching moment coefficient (CM) is obtained from the simulations. The data is represented in curves against angle of attack to measure the performance of BWB prototype with horizontal stabilizer. From the simulation, configuration with far distance and large horizontal stabilizer gives steeper negative pitching moment slope indicating better static stability of the aircraft.

Weight assessment for a blended wing Body-Unmanned aerial vehicle implementing boundary layer ingestion

Boundary Layer Ingestion (BLI) has been studied extensively for implementation in Blended Wing Body (BWB) transport aircrafts, and it has been reported that BLI offers potential benefits mainly in terms of energy, improving the propulsive efficiency of a propulsion system and reducing the fuel consumption. This paper examines potential benefits of BLI related with a reduction on the Take-Off Gross Weight (TOGW) for a BWB-Unmanned Aerial Vehicle (UAV). It is discussed the methodology for weight estimation of a BWB-UAV through parametric models. To evaluate the benefits of BLI in terms of weight reduction, it has been taken into account the removal of pylons and the nacelle weight reduction when embedding nacelles into the airframe. The validation of the parametric models, and the case of study have been carried out for the aircraft NASA X-48B. The results show a reduction in TOGW between 8% and 19% when removing pylons and embedding nacelles into the airframe.

An efficient aerodynamic shape optimization of blended wing body UAV using multi-fidelity models

This paper presents a novel optimization technique for an efficient multi-fidelity model building approach to reduce computational costs for handling aerodynamic shape optimization based on high-fidelity simulation models. The wing aerodynamic shape optimization problem is solved by dividing optimization into three steps—modeling 3D (high-fidelity) and 2D (low-fidelity) models, building global meta-models from prominent instead of all variables, and determining robust optimizing shape associated with tuning local meta-models. The adaptive robust design optimization aims to modify the shape optimization process. The sufficient infilling strategy—known as adaptive uniform infilling strategy—determines search space dimensions based on the last optimization results or initial point. Following this, 3D model simulations are used to tune local meta-models. Finally, the global optimization gradient-based method—Adaptive Filter Sequential Quadratic Programing (AFSQP) is utilized to search the neighborhood for a probable optimum point. The effectiveness of the proposed method is investigated by applying it, along with conventional optimization approach-based meta-models, to a Blended Wing Body (BWB) Unmanned Aerial Vehicle (UAV). The drag coefficient is defined as the objective function, which is subjected to minimum lift coefficient bounds and stability constraints. The simulation results indicate improvement in meta-model accuracy and reduction in computational time of the method introduced in this paper.

AERODYNAMIC OF UITM'S BLENDED-WING-BODY UNMANNED AERIAL VEHICLE BASELINE-II EQUIPPED WITH ONE CENTRAL VERTICAL RUDDER

In this paper, a study of aerodynamic characteristics of UiTM's Blended-Wing-Body Unmanned Aerial Vehicle (BWB-UAV) Baseline-II in terms of side force, drag force and yawing moment coefficients are presented through Computational Fluid Dynamics (CFD) simulation. A vertical rudder is added to the aircraft at the rear centre part of the fuselage as yawing control surface. The study consists of varying the side slip angles for various rudder deflection angles and to plot the results for each aerodynamic parameter. The comparison with other yawing control surface for the same aircraft obtained previously are also presented. For validation purpose, the lift and drag coefficients are compared with the results obtained from wind tunnel experiments.

The Effects of Split Drag Flaps on Directional Motion of UiTM’s BWB UAV Baseline-II E-4: Investigation Based on CFD Approach

This paper presents a study about split drag flaps as control surfaces to generate yawing motion of a blended wing body aircraft. These flaps are attached on UiTM’s Blended Wing Body (BWB) Unmanned Aerial Vehicle (UAV) Baseline-II E-4. Deflection of split drag flaps on one side of the wing will produce asymmetric drag force and, as consequences, yawing moment will be produced. The yawing moment produced will rotate the nose of the BWB toward the wing with deflected split drag flaps. The study has been carried out using Computational Fluid Dynamics to obtain aerodynamics data with respect to various sideslip angles (ß). The simulation is running at 0.1 Mach number or about 35 m/s. Results in terms of dimensionless coefficient such as drag coefficient (CD), side force coefficient (CS) and yawing moment coefficient (Cn) are used to observe the effects of split drag Subscript text flaps on the yawing moment. All the results obtained shows linear trends for all curves with respect to sideslip angles (ß).

Wind Tunnel Experiments and CFD Analysis of Blended Wing Body (BWB) Unmanned Aerial Vehicle (UAV) at Mach 0.1 and Mach 0.3

This paper discusses the aerodynamics behavior of a baseline design of a Blended Wing Body (BWB) aircraft developed at MARA University of Technology (UiTM). Two methods of analysis are presented, i.e. Steady-state, three- dimensional Computational Fluid Dynamics (CFD) of the BWB at Mach 0.3 and Wind Tunnel experiments on 1/6 scaled half model of the BWB at Mach 0.1. In both methods of analysis, Lift Coefficient (CL), Drag Coefficient (CD) and Pitching Moment Coefficient (CM) are measured and compared at respective Mach numbers with respect to variation of angle of attack. Pressure contours and Mach number contours are plotted and the turbulence area is predicted, both extracted from CFD analysis. Visualization using mini tuft during wind tunnel tests is also executed to complete the analysis where the stall progression patterns can be clearly observed. The presented BWB UAV design here has achieved an unprecedented capability in terms of sustainability of flight at high angle of attack, low parasite drag coefficient and decent maximum lift coefficient. Some recommendations for future improvement of the BWB are given.