Contemporary frame of measurement and assessment of wind-tunnel flow quality in a low-speed facility

This paper presents analyses of the effect of blowing flow control and variations on front geometry towards the reduction of aerodynamic drag on vehicle models. Blowing flow control is an alternative measure in modifying the onset of flow separation in the boundary layer on the surface of the vehicle. The modification is expected to reduce the dominating influence of the separation area on the total drag. Conducted in computational and experimental approaches, the research investigated the effect of frontal slant angle variations (θ) of 25°, 30° and 35° towards the reduction of aerodynamic drag on vehicle models on the application of blowing flow control with upstream and blowing speed of 16.7 m/s and 0.5 m/s, respectively. Load cells were used in the experimental method to validate the reduction of aerodynamic drag obtained from computational method. It is indicated that the effects of blowing flow control and variations on front geometry are significant in the increasing on pressure coefficients and the reduction of aerodynamic drag on vehicle models. The largest increase on pressure coefficients of 38.93% is indicated on the vehicle model with θ=35°, while the largest reduction of aerodynamic drag occurred on the same model with the values of 14.81 and 12.54 for computational and experimental methods, respectively.

Section: Methodsmentioning

confidence: 99%

Effect of blowing flow control and front geometry towards the reduction of aerodynamic drag on vehicle models

Tarakka¹,

Salam²,

Jalaluddin³

et al. 2019

“…Simulation of the missile engine was performed with a high-pressure cold-air pneumatic installation, Figure 7. [8]. The model was fixed to the mechanism for changing the angle of attack of the model through rear tail sting.…”

Section: Wind Tunnel Modelmentioning

confidence: 99%

“…CAD/CAM model with jet simulation installationThe missile model has internal space of adequate size for setting up five-component wind tunnel balance VTI385, with diameter of 38mm and housing of the jet installation,Figure 8 [8]…”

mentioning

confidence: 99%

Experimental and numerical research of the influence of thrust vector control on the missile aerodynamics by cold and hot jet simulations

Ocokoljić¹,

Rašuo²,

Damljanović³

et al. 2020

Self Cite

The flow field phenomena that occur as a result of thrust vector control (TVC) system activity on a missile with lateral jets are very complex and influence all other components of the missile. Influence is more significant when TVC is generating commands, when jets are asymmetrically directed. The main goal of these study was to determine the influence of of the hot rocket motor's combustion products on the basis of the CFD model proven with the cold-jet simulation. Based on obtained experimental aerodynamic coefficients for the cold-jet simulation the preliminary aerodynamic CFD model was designed. Three-dimensional Reynolds averaged Navier-Stokes numerical aerodynamic and hot-jet simulations were carried out to predict the aerodynamic loads of the missile based on the finite volume method. The study resulted in the definition of a methodology for the investigation of the jet reaction effects in a wind tunnel. A method for determining of the TVC system interference on the aerodynamic characteristics, as a basic prerequisite for structural, stability and performance analysis, was proposed. Mutual verification and validation process was carried out through experiment and proper application of the commercial CFD software code for calculation aerodynamic effects of the hot gases lateral jets on the performance of a guided missile. Experimental and computational results of the pitching moment coefficients are presented and agreed well with.

“…Lift curve slope coefficient, which is used to measure the aerodynamic performance of the airfoil, is reported to be significant based on Solid-wall interface and Reynold's number [26]. Uncertainty in the wind tunnel calibration, which includes airfoil dimensional accuracy is reported to result in the error of 0.04-0.18% in transducer full scale for different moments [27]. Pioneering work on fluid flow study shows that roughness of the substrate has clear effect on the performance of fluid flow in networks and it was estimated that effect is relatively simple, yet important [28].…”

Section: Verification Of Prediction Model Using Naca0012 Airfoil-casementioning

confidence: 99%

Effect of electroplating on surface roughness and dimension of FDM parts at various build orientations

Sugavaneswaran¹,

Thomas²,

Azad³

2019

Fused deposition modeling is used in industry, mainly for prototyping the designs modeled through CAD software. The most common build material used in this technology is ABS (Acrylonitrile Butadiene Styrene) plastic and it is one of the common methods used to produce ABS parts of mid quantity series of high complexity objects. But due to stair step effect, the products produced by this method have high roughness compared to ABS parts produced by conventional method like injection molding process. So FDM parts are generally electroplated to meet the industry requirements. However, electroplating has a significant effect on the roughness and the dimension of the parts and this effect varies significantly at different part orientation. Therefore, in this work, experimentation is done to study the electroplating effect on FDM parts surface roughness and dimension at various surface angles. From the experimented data base of electroplated test parts, advanced interpolation method is used to predict the surface roughness and change in dimension of electroplated FDM parts at other orientation. Interpolation helps to find out the best build orientation for any significant features of a part to get good/ required surface finish and gives dimension allowance required before electroplating. The proposed methodology is validated with a case study of prediction model using NACA 0012 airfoil.