## 7 Conclusions  
An MHD thin film flow of second grade nanofluid holding SWCNTs and MWCNTs with heat flux model of Cattaneo-Christov and entropy generation is analyzed in this article. The flow is considered past a linearly extending sheet. The final remarks of the current analysis are  
1. Velocity profile heightens with the increase in nanoparticles volume fraction and second grade fluid parameter, whereas the declining impact is observed via magnetic parameter, film thickness, and unsteadiness parameter.
2. Temperature profile heightens with the escalation in second grade fluid parameter, nanoparticles volume fraction, radiation parameter, and heat source/sink parameters while a reducing influence is observed via film thickness, unsteadiness parameter, and thermal relaxation parameter.
3. Surface drag force escalates with the higher values of nanoparticles volume fraction, unsteadiness parameter, film thickness, magnetic parameter, and second grade fluid parameter.
4. Thermal transfer rate surges with the heightening values of nanoparticles volume fraction, unsteadiness parameter, and film thickness, whereas a reducing effect is observed via heat source/sink parameters.
5. The higher value of Reynolds number augmented the entropy optimization.
6. Entropy generation increases with higer values of magnetic parameter and Brinkman number and Reynolds number.
7. The entropy \(N_{G}(\eta)\) declines with the rise of temperature difference ratio parameter.  
**Author Contributions:** Conceptualization, methodology, software, validation, writing--original draft preparation, writing--review and editing, Z.S., E.O.A.; W.A. and A.D. conceptualization, methodology, software, visualization, writing--review and editing; E.O.A. and M.Z.U., writing--review and editing, visualization, project administration, funding acquisition, investigation, resources. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This project was funded by the Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah under grant no. (RG-85-130-38).  
**Acknowledgments:** This project was funded by the Deanship of Scientific Research (DSR) at King Abdulaziz University, University, Jeddah under grant no. (RG-85-130-38). The authors, therefore, gratefully acknowledge DSR for technical and financial support.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
**Nonenclature**  
\(u,v[m/s]\) Components of Velocity \(\Pr[-]\) and Prandtl Number \(x,y[m]\) Coordinate of axes \(C_{f}[-]\) Skin friction coefficient \(B_{0}[kg/s^{2}A]\) Magnetic field \(Nu[-]\) Nusselt number \(\xi[m^{2}/s]\) Stream function \(\Re[-]\) Local Reynolds number \(T[K]\) Temperature \(S[-]\) Unsteadiness parameter \(T_{w}[K]\) Temperature at the surface \(E_{gm}[kg/m.K.S^{3}]\) Entropy generation rate \(T_{\infty}[K]\) Ambient fluid temperature \(N_{G}[-]\) Entropy generation number \(\lambda_{2}[-]\) Cattaneo-Christov parameter \(k[W/mK]\) Thermal conductivity \(q^{\prime\prime}\) Hear source/sink \(\lambda[-]\) Film thickness \(\alpha_{2}[m^{2}/s]\) Thermal diffusivity \(\Delta T[-]\) Temperature difference \(c_{p}[J/Kg.K]\) Specific heat \(\rho[kg/m^{3}]\) Density \(\gamma[-]\) Thermal relaxation parameter \(\mu_{w}[kg/m.S^{2}]\) Shear stress \(Br[-]\) Brinkmann number \(\mu_{w}[m/s]\) Stretching velocity \(M[-]\) Magnetic parameter \(\sigma^{\prime}[-]\) Stephan-Boltzmann constant \(R[-]\) Thermal radiation parameter \(k[-]\) Mean absorption coefficient \(\mu[kg/ms]\) Dynamic viscosity \(\beta[-]\) Thermal expansion coefficient \(A^{*},B^{*}[-]\) Non-uniform heat source/sink \(\varepsilon[\text{degrees}]\) Aligned angle (degrees) \(\phi[nm]\) Volume fraction of the nanoparticles \(\phi[nm]\) Volume